Vehicle Dynamic Suspension -...

Vehicle Dynamic Suspension

Refer to Wiring Diagrams Cell 40, Air Suspension (VAPS) for schematic and connector information.

Principles of Operation

WARNING:

� Before repairing or installing any air suspension component(s), turn off the air suspension switch or disconnect the battery ground cable to prevent vehicle damage or personal injury.

� Do not attempt to install or inflate any rear air spring that has become unfolded to prevent vehicle damage or personal injury.

� Failure to observe the following procedures may result in a sudden failure of the air spring or suspension system.

� Any rear spring which is unfolded must be refolded prior to being installed in a vehicle.

� The air spring refolding procedure should only be used for an air spring which has never supported the vehicle's weight while in the improperly folded position.

� Vehicles with an incorrectly folded air spring(s) found after the vehicle has been driven, must have a new air spring installed.

� Do not attempt to inflate any air spring which has been collapsed while uninflated from the rebound hanging position to the jounce stop.

� When installing a new air spring, care must be taken not to apply a load to the suspension until springs have been inflated using the air spring fill procedure.

� After inflating an air spring in hanging position, it must be inspected for proper shape.

Dual Action System

The suspension system incorporates a rear load leveling system that maintains the vehicle at the proper ride height under varying conditions of vehicle load, and an optional road calibrated suspension ride control system that varies the damping of the shock absorbers between soft and firm.

The rear load leveling system uses air springs to support the vehicle weight. The quantity of air in the rear air spring is controlled by the vehicle dynamic module (VDM) to maintain a predetermined vehicle ride height. Each air spring has an air spring solenoid to control air flow into and out of each air spring.

The optional ride control system uses four shocks with electronically controlled actuators. The shock actuators are internally mounted on the lower bodies of the front spring and shock assemblies and the rear shocks. The action of the shock actuators is controlled by the VDM. The VDM sends a signal to an appropriate shock actuator which switches to either soft or firm damping. Normally the shock actuator setting is in a soft, luxury car mode. This is done by causing an electric current flow through the actuator, which induces electromagnetic force that moves the shock actuator from a firm to a soft position. When driving situations require, the setting is switched to a firm, high performance control mode. This is done by removing power to the actuator, allowing the shock actuator to return to the firm mode.

The shock actuators are not replaced separately. If testing indicates an actuator failure, the entire shock absorber must be replaced.

Vehicle Dynamic Module

A microprocessor controls the air suspension and ride control systems. The microprocessor and its support hardware are contained in the vehicle dynamic module (VDM). It responds to signals from various sensors in the vehicle to maintain the desired ride height while the vehicle is either moving or stopped. It accomplishes this by opening and closing solenoid valves (5311). It also turns on the compressor through the compressor relay or opens the vent solenoid in response to signal inputs from the air suspension height sensor. It also controls the shock actuators, if equipped.

Normally, the VDM uses a 45-second averaging interval to determine when fill and vent operations are needed. However, door switch signals' inputs can override the 45-second averaging interval so fill and vent operations can begin immediately, if needed.

Air Suspension Service Switch

The air suspension service switch provides the system enable signal to the vehicle dynamic module in the ON position only.

SECTION 204-05: Vehicle Dynamic Suspension 2001 Continental Workshop Manual

DIAGNOSIS AND TESTING Procedure revision date: 04/29/2004

Special Tool(s)

Vacuum Tester or equivalent 014-R1054

Battery Charger or equivalent 035-00003

73 Digital Multimeter or equivalent 105-R0051

EEC-IV 60-Pin Breakout Box or equivalent 418-F010 (014-00322)

Worldwide Diagnostic System (WDS) 418-F224 New Generation STAR (NGS) Tester 418-F052 or equivalent scan tool

of 362001 Continental Workshop Manual

12/11/2012http://www.fordtechservice.dealerconnection.com/pubs/content/~WS1E/~MUS~LEN/18/...

Air Compressor

The compressor contains a thermal overload circuit breaker. The circuit breaker automatically resets after a cool down period and after being tripped by excessive compressor motor heat.

The air compressor assembly consists of the compressor pump, electric motor, and vent solenoid (must be installed as an assembly).

Air Suspension Height Sensor

The air suspension height sensor (5359) provides a continuous voltage signal corresponding to vehicle ride height. For instance, when the sensor is fully compressed, the voltage signal sent to the vehicle dynamic module (VDM) is 4.5 volts. When the sensor is fully extended, the voltage signal to the vdm is 0.5 volt.

Each one of the air suspension height sensors measures the actual difference between known reference points so that the VDM can respond to variations in ride height.

If the wheel speed and travel are above a predetermined level, the shock actuators are switched to the firm position. This reduces the chance of grounding out the suspension when traveling over rough road surfaces.

Body roll during extended, high lateral-force turns (freeway exits) are also neutralized to prevent unwanted leveling actions at these times.

Air Spring Solenoid Valve

Never rotate an air spring solenoid valve to the release slot in the end cap fitting until all pressurized air has escaped from the spring to prevent damage or injury.

The air spring solenoid allows air to enter and exit the air spring during leveling corrections. The air spring solenoid valve is electrically operated and controlled by the VDM.

Vent Solenoid

The vent solenoid allows air to escape from the system during venting corrections. The vent solenoid is located in the air compressor cylinder head and shares a common electrical connector with the motor. The vent solenoid is enclosed in the cylinder head casting, which forms an integral vent solenoid housing that allows the vent solenoid tip to enter the pressurized side of the system. Air leakage past the vent solenoid tip is prevented by an O-ring seal.

When it is determined that a corner of the vehicle is high, the vent solenoid opens to provide an escape route for the pressurized air. The vehicle will not lower unless the air spring solenoid is also opened to allow air to leave the springs.

Inspection and Verification

1. Verify the customer concern.

2. Visually inspect for obvious signs of mechanical and electrical damage. If the inspection reveals an obvious concern that is readily repaired, correct the concern before continuing with Inspection and Verification.

Visual Inspection Chart

3. If the concern remains after the inspection, connect the scan tool to the data link connector (DLC) located beneath the instrument panel and select the vehicle to be tested from

the scan tool menu. If the scan tool does not communicate with the vehicle:

� check that the program card is properly installed.

� check the connections to the vehicle.

� check the ignition switch position.

4. If the scan tool still does not communicate with the vehicle, refer to the scan tool manual.

5. Carry out the DATA LINK DIAGNOSTIC TEST. If the scan tool responds with:

� CKT914, CKT915 or CKT70= ALL ECUS NO RESP/NOT EQUIP, refer to Section 418-00.

� NO RESP/NOT EQUIP for Vehicle Dynamic Module (VDM), go to Pinpoint Test A.

� SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the Vehicle Dynamic Module.

6. If the DTCs retrieved are related to the concern, go to Vehicle Dynamic Module Diagnostic Trouble Code (DTC) Index.

7. If no DTCs related to the concern are retrieved, proceed to Symptom Chart to continue diagnostics.

VDM Diagnostic Trouble Code (DTC) Index

VDM Diagnostic Trouble Code (DTC) Index

Mechanical Electrical

� Restricted suspension movement � Excessive vehicle load � Detached, disconnected, or incorrectly mounted height sensor � Crimped, kinked, or leaking air line � Damaged air spring and shock assembly(s)

� Air suspension switch is OFF � Blown fuse:

� Battery junction box (BJB) — maxi Fuse 11 (60A), mini Fuse 4 (30A) � Central junction box (CJB) — Fuse 28 (10A)

� Loose connectors � Corroded connectors

DTCS Description Source Action

B1317 Battery Voltage High. VDM GO to Pinpoint Test C.

B1318 Battery Voltage Low. VDM GO to Pinpoint Test D.

B1342 ECU Internal Fault. VDM GO to Pinpoint Test E.

C1722 Air Suspension Height Sensor Power Circuit Short To Battery. VDM GO to Pinpoint Test F.

C1723 Air Suspension Height Sensor Power Circuit Short To Ground. VDM GO to Pinpoint Test G.

C1735 Air Suspension LR Corner Up Timeout. VDM GO to Pinpoint Test H.

C1736 Air Suspension LR Corner Down Timeout. VDM GO to Pinpoint Test I.



VDM Parameter Identification (PID) Index

VDM Parameter Identification (PID) Index

VDM Active Command Index

VDM Active Command Index

C1737 Air Suspension RR Corner Up Timeout. VDM GO to Pinpoint Test H.

C1738 Air Suspension RR Corner Down Timeout. VDM GO to Pinpoint Test I.

C1770 Air Suspension Vent Solenoid Output Circuit Failure. VDM GO to Pinpoint Test J.

C1773 Air Suspension Vent Solenoid Output Circuit Short To Ground. VDM GO to Pinpoint Test K.

C1790 Air Suspension LR Air Spring/Solenoid Output Circuit Failure. VDM GO to Pinpoint Test L.

C1793 Air Suspension LR Air Spring/Solenoid Output Circuit Short To Ground. VDM GO to Pinpoint Test M.

C1795 Air Suspension RR Air Spring/Solenoid Output Circuit Failure. VDM GO to Pinpoint Test L.

C1798 Air Suspension RR Air Spring/Solenoid Output Circuit Short To Ground. VDM GO to Pinpoint Test M.

C1820 Air Compressor Request Exceeding Maximum Timing. VDM GO to Pinpoint Test N.

C1840 Air Suspension Disable Switch Circuit Failure. VDM GO to Pinpoint Test G.

C1842 Air Suspension Disable Switch Circuit Short To Power. VDM GO to Pinpoint Test F.

C1881 Air Suspension RF Height Sensor Circuit Failure. VDM GO to Pinpoint Test O.

C1884 Air Suspension RF Height Sensor Circuit Short To Ground. VDM GO to Pinpoint Test P.

C1885 Air Suspension RR Height Sensor Circuit Failure. VDM GO to Pinpoint Test O

C1888 Air Suspension RR Height Sensor Circuit Short To Ground. VDM GO to Pinpoint Test P.

C1889 Air Suspension LF Height Sensor Circuit Failure. VDM GO to Pinpoint Test O.

C1892 Air Suspension LF Height Sensor Circuit Short To Ground. VDM GO to Pinpoint Test P.

C1893 Air Suspension LR Height Sensor Circuit Failure. VDM GO to Pinpoint Test O.

C1896 Air Suspension LR Height Sensor Circuit Short To Ground. VDM GO to Pinpoint Test P.

C1897 Steering VAPS II Circuit Loop Failure. VDM REFER to Section 211-00.

C1901 Ride Control RR Shock Actuator Circuit Failure. VDM GO to Pinpoint Test Q.

C1904 Ride Control RR Shock Actuator Circuit Short To Ground. VDM GO to Pinpoint Test R.

C1905 Ride Control LR Shock Actuator Circuit Failure. VDM GO to Pinpoint Test Q.

C1908 Ride Control LR Shock Actuator Circuit Short To Ground. VDM GO to Pinpoint Test R.

C1909 Ride Control RF Shock Actuator Circuit Failure. VDM GO to Pinpoint Test Q.

C1912 Ride Control RF Shock Actuator Circuit Short To Ground. VDM GO to Pinpoint Test R.

C1913 Ride Control LF Shock Actuator Circuit Failure. VDM GO to Pinpoint Test Q.

C1916 Ride Control LF Shock Actuator Circuit Short To Ground. VDM GO to Pinpoint Test R.

C1929 Air Suspension Compressor Relay Circuit Failure. VDM GO to Pinpoint Test S.

C1931 Air Suspension Compressor Relay Circuit Short To Power. VDM GO to Pinpoint Test T.

U1027 SCP Invalid or Missing Data For Engine RPM. PCM CARRY OUT the PCM self-test.

U1041 SCP Invalid or Missing Data For Vehicle Speed. ABS CARRY OUT the ABS self-test.

U1181 SCP Invalid or Missing Data For Personalization (Memory) Features. VIC CARRY OUT the VIC self-test.

U1262 SCP Communication Bus Fault. REPAIR all other DTCs. If DTC U1262 is still retrieved, REFER to Section 418-00.

PID Description Expected Values

CCNTVDM Number Of Continuous DTCs On VDM One count per bit

VSS_VDM Vehicle Speed Sensor Via SCP Network 1/128

VAPS_IN VAPS II Input Current Input 0-100%

VAPSOUT VAPS II Output Current Set Point 0-100%

HGT_PWR Height Sensor Power Volts

ASLRSOL Left Rear Air Spring Solenoid ON, OFF, SHORTVBAT, SHORTGND, OPEN

ASRRSOL Right Rear Air Spring Solenoid ON, OFF, SHORTVBAT, SHORTGND, OPEN

AS_COMP Air Suspension Compressor Relay State ON, OFF, SHORTVBAT, SHORTGND, OPEN

AS_VNT Vent Solenoid Output State ON, OFF, SHORTVBAT, SHORTGND, OPEN

AS_TRIM Air Suspension At Accurate Trim TRIM, notTRIM

ASDISSW Air Suspension Inhibit Switch ON, OFF

RRSHOCK Right Rear Shock Actuator State FIRM, SOFT, OPEN, B+, GND

LRSHOCK Left Rear Shock Actuator State FIRM, SOFT, OPEN, B+, GND

RFSHOCK Right Front Shock Actuator State FIRM, SOFT, OPEN, B+, GND

LFSHOCK Left Front Shock Actuator State FIRM, SOFT, OPEN, B+, GND

DOORVDM External Access Door Ajar Switch AJAR, notAJAR

IGN_RUN Ignition Switch State RUN, notRUN

VBATVDM Battery Voltage Volts

LF_HGT Left Front Height Sensor mm

LR_HGT Left Rear Height Sensor mm

RF_HGT Right Front Height Sensor mm

RR_HGT Right Rear Height Sensor mm

VAPSSET Vehicle Dynamics Feature Option Selection 0,1



Symptom Chart

NOTE: Refer to the Wiring Diagrams for connector numbers stated in the Pinpoint Tests.

Pinpoint Tests

PINPOINT TEST A: NO COMMUNICATION WITH THE MODULE — VEHICLE DYNAMIC MODULE

Active Command Display Action

Module Sleep — —

Semi-Active Ride Control LFSHSOFT ON, OFF

RFSHSOFT ON, OFF

LRSHSOFT ON, OFF

RRSHSOFT ON, OFF

Air Suspension Control HGT POWER ON, OFF

LR SOL ON, OFF

RR SOL ON, OFF

COMPRESSR ON, OFF

VENT ON, OFF

WARN MSG ON, OFF

VAPS II Output Pulse Control VAPSIIOUT 0-100%

Symptom Chart

Condition Possible Sources Action

� No communication with the vehicle dynamic module (VDM) � BJB Fuse 4 (30A) � CJB Fuse 28 (10A). � Circuitry. � Air suspension control

module. � Air suspension switch.

� GO to Pinpoint Test A.

� Unable to enter auto test diagnostics � Air suspension control module.

� GO to Pinpoint Test B.

� The compressor is inoperative � BJB Fuse 11 (60A). � Circuits. � Air compressor relay. � Air compressor.

� GO to Pinpoint Test U.

� The air suspension system is inoperative — one or more corners low, compressor operates

� Air line. � Air spring solenoid. � Air compressor. � Air spring. � Ride height sensor.

� GO to Pinpoint Test V.

CONDITIONS DETAILS/RESULTS/ACTIONS

A1 CHECK CIRCUIT 875 (BK/LB) FOR OPEN

Connect the EEC-IV 60-Pin Breakout Box to VDM C408.

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB), and ground.

� Is the resistance less than 5 ohms?

Yes GO to A2.

No REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

A2 CHECK CIRCUIT 418 (DG/YE) FOR OPEN

BJB Mini Fuse 4 (30A)

Measure the resistance between the load side of BJB mini Fuse 4 (30A), Circuit 418 (DG/YE) and EEC-IV 60-Pin Breakout Box Pin 57, Circuit 418 (DG/LG).



PINPOINT TEST B: UNABLE TO ENTER SELF-TEST DIAGNOSTICS


Yes GO to A3.


A3 CHECK CIRCUIT 1050 (LG/VT) FOR OPEN

CJB Fuse 28 (10A)

Measure the resistance between the load side of CJB Fuse 28 (10A), Circuit 1050 (LG/VT) and EEC-IV 60-Pin Breakout Box Pin 1, Circuit 1050 (LG/VT).


Yes REFER to Section 418-00.



B1 CHECK THE COMMUNICATION TO THE VDM

Check the communication to the VDM.



PINPOINT TEST C: DTC B1317: BATTERY VOLTAGE HIGH

PINPOINT TEST D: DTC B1318: BATTERY VOLTAGE LOW

� Does scan tool communicate with the VDM?

Yes INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM) . CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

No GO to Pinpoint Test A.


C1 CHECK BATTERY FOR HIGH VOLTAGE

Verify that lights, radio and all accessories are off.

Measure the voltage between battery terminals.

� Is the voltage greater than 14.5 volts?

Yes REPAIR the charging system. REFER to Section 414-00.

No If DTC B1317 is a continuous DTC and is not encountered during self-test, CLEAR the DTCs. REPEAT the self-test. If DTC 1317 is a self-test DTC, INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.


D1 CHECK BATTERY FOR LOW VOLTAGE

Verify that lights, radio and all accessories are off.

Measure the voltage between battery terminals.

� Is the voltage greater than 12.5 volts?

Yes GO to D2.

No REPAIR the charging system. REFER to Section 414-00.

D2 CHECK VOLTAGE AT VEHICLE DYNAMIC MODULE (VDM)

VDM C408

Connect the EEC-IV 60-Pin Breakout Box to VDM C408. Do not connect the VDM.

Verify that lights, radio and all accessories are turned off.

Measure the voltage between EEC-IV 60-Pin Breakout Box Pins as follows:

EEC-IV 60-Pin Breakout Box Pin, Circuit EEC-IV 60-Pin Breakout Box Pin, Circuit

36, Circuit 418 (DG/YE) 40, Circuit 875 (BK/LB)




PINPOINT TEST E: DTC B1342: ECU INTERNAL FAULT

PINPOINT TEST F: DTC C1722: AIR SUSPENSION HEIGHT SENSOR POWER CIRCUIT SHORT TO POWER, DTC C1842 AIR SUSPENSION DISABLE SWITCH CIRCUIT SHORT TO POWER




� Is the voltage greater than 10 volts?

Yes If DTC B1318 is a continuous DTC and is not encountered during self-test, CLEAR the DTCs. REPEAT the self-test. If DTC 1318 is a self-test DTC, INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

No GO to D3.

D3 CHECK VDM GROUND CIRCUITS

Measure the resistance between the following EEC-IV 60-Pin Breakout Box test pins, and ground.

� 40, Circuit 875 (BK/LB)

� 60, Circuit 875 (BK/LB)

� Are the resistances less than 5 ohms?

Yes CHECK Circuit 418 (DG/YE) for open. REPAIR as necessary. REPEAT the self-test.

No REPAIR the Circuit. CLEAR the DTCs. REPEAT the self-test.


E1 CHECK FOR CONTINUOUS DTCS

Retrieve and document continuous DTCs.

� Is DTC B1342 present?

Yes INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

No The system is operating normally.


F1 CHECK HEIGHT SENSOR CONNECTORS

Disconnect height sensor C413, and if equipped, C406, C1014, and C1015.



Check the height sensor connectors for corrosion, bent pins and damaged wires.

� Are the height sensor connectors worn or damaged?

Yes REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.

No RECONNECT the height sensor(s). GO to F2 .

F2 CHECK AIR SUSPENSION SWITCH CONNECTOR

Air Suspension Switch C476

Check air suspension switch C476 for corrosion, bent pins and damaged wires.

� Is the air suspension switch C476 worn or damaged?


No GO to F3.

F3 CHECK VEHICLE DYNAMIC MODULE (VDM) CONNECTOR

VDM C408

Check VDM C408 for corrosion, bent pins and damaged wires.

� Is the VDM C408 worn or damaged?


No GO to F4.

F4 CHECK CIRCUIT 425 (BR/PK) FOR SHORT TO POWER

Connect EEC-IV 60-Pin Breakout Box to VDM C408.

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 48, Circuit 425 (BR/PK), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).

� Is voltage present?

Yes REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.

No GO to F5.

F5 CHECK CIRCUIT 426 (RD/BK) FOR SHORT TO POWER

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).



PINPOINT TEST G: DTC C1723: AIR SUSPENSION HEIGHT SENSOR POWER CIRCUIT SHORT TO GROUND, DTC C1840: AIR SUSPENSION DISABLE SWITCH CIRCUIT FAILURE


Yes REPAIR Circuit 426 (RD/BK). CLEAR the DTCs. REPEAT the self-test.

No RECONNECT air suspension switch C476. GO to F6 .

F6 CHECK VOLTAGE BETWEEN CIRCUIT 426 (RD/BK) AND CIRCUIT 432 (BK/PK)

Connect EEC-IV 60-Pin Breakout Box to the VDM.

Verify that the air suspension switch is in the ON position.

Scan Tool

Trigger VDM active command HGT POWER ON.

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK).

� Is the voltage between 4.8 volts and 5.2 volts?

Yes GO to F7.

No INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

F7 CHECK HEIGHT SENSORS

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK) as each height sensor is reconnected.

� Is the voltage between 4.8 volts and 5.2 volts after each height sensor is reconnected?

Yes CARRY OUT the Wiggle Test. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.

No INSTALL a new height sensor; REFER to Height Sensor. CLEAR the DTCs. CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.


G1 CHECK HEIGHT SENSOR CONNECTORS



Disconnect height sensor C413, and if equipped, C406, C1014, and C1015.

Check the height sensor connectors for corrosion, bent pins and damaged wires.

� Are the height sensor connectors worn or damaged?


No RECONNECT the height sensor(s). GO to G2 .

G2 CHECK AIR SUSPENSION SWITCH CONNECTOR

Air Suspension Switch C476

Check air suspension switch C476 for corrosion, bent pins and damaged wires.

� Is the air suspension switch C476 worn or damaged?


No GO to G3.

G3 CHECK VEHICLE DYNAMIC MODULE (VDM) CONNECTOR

VDM C408

Check VDM C408 for corrosion, bent pins and damaged wires.

� Is the VDM C408 worn or damaged?


No GO to G4.

G4 CHECK AIR SUSPENSION SWITCH

Measure the resistance between air suspension switch terminals with the switch ON and then OFF.

� Is the resistance with the air suspension switch ON less than 5 ohms and with the air suspension

switch OFF greater than 10,000 ohms?

Yes GO to G5.

No INSTALL a new air suspension switch. CLEAR the DTCs. REPEAT the self-test.

G5 CHECK CIRCUIT 425 (BR/PK)

Connect EEC-IV 60-Pin Breakout Box to VDM C408.

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 48, Circuit 425 (BR/PK), and air suspension switch C476, Circuit 425 (BR/PK); and between EEC-IV 60-Pin Breakout Box Pin 48, Circuit 425 (BR/PK), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).

� Is the resistance less than 5 ohms between EEC-IV 60-Pin Breakout Box and switch, and greater



than 10,000 ohms between EEC-IV 60-Pin Breakout Box pins?

Yes GO to G6.

No REPAIR Circuit 425 (BR/PK). CLEAR the DTCs. REPEAT the self-test.

G6 CHECK CIRCUIT 426 (RD/BK)

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and air suspension switch C476, Circuit 426 (RD/BK); and between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).

� Is the resistance less than 5 ohms between EEC-IV 60-Pin Breakout Box and air suspension switch;

and greater than 10,000 ohms between EEC-IV 60-Pin Breakout Box pins?

Yes GO to G7.

No REPAIR Circuit 426 (RD/BK). CLEAR the DTCs. REPEAT the self-test.

G7 CHECK VOLTAGE BETWEEN CIRCUIT 426 (RD/BK) AND CIRCUIT 432 (BK/PK)


Scan Tool


Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK).


Yes GO to G8.

No INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CLEAR the DTCs. CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

G8 CHECK HEIGHT SENSORS

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK) as each height sensor is reconnected.



PINPOINT TEST H: DTC C1735: AIR SUSPENSION LR CORNER UP TIMEOUT, DTC C1737: AIR SUSPENSION RR CORNER UP TIMEOUT

� Is the voltage between 4.8 volts and 5.2 volts after each height sensor is reconnected?

Yes INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM).



H1 CHECK FOR AIR COMPRESSOR ASSEMBLY OPERATION

Scan Tool

Trigger VDM active command COMPRESSR ON then OFF.

� Does the air compressor turn on and off?

Yes GO to H2.

No GO to Pinpoint Test U.

H2 CHECK FOR AIR SPRING SOLENOID FUNCTION

Trigger VDM active commands RR SOL or LR SOL, and COMPRESSR ON.

� Does a corner raise?

Yes TRIGGER VDM active commands RR SOL or LR SOL, and COMPRESSR OFF. GO to H3 .

No TRIGGER VDM active commands RR SOL or LR SOL, and COMPRESSR OFF. GO to Pinpoint Test V.

H3 CHECK HEIGHT SENSOR MOUNTING POINTS

Check the height sensor mounting points.



PINPOINT TEST I: DTC C1736: AIR SUSPENSION LR CORNER DOWN TIMEOUT, DTC C1738: AIR SUSPENSION RR CORNER DOWN TIMEOUT

� Are the mounting points damaged or are the height sensors disconnected from the ball studs?

Yes REPAIR as necessary. CLEAR the DTCs. CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

No GO to H4.

H4 CHECK FOR HEIGHT SENSOR OPERATION


Monitor VDM PID LR_HGT or RR_HGT.

Disconnect the selected height sensor from the lower ball stud.

Extend and compress the selected height sensor over its full range of travel.

� Does the displayed length for the selected height sensor vary as the length of the height sensor

changes?

Yes TRIGGER VDM active command HGT POWER OFF. RECONNECT height sensor(s). CARRY OUT the Accurate Trim Test. CLEAR the DTCs. REPEAT the self-test.

No TRIGGER VDM active command HGT POWER OFF. RECONNECT height sensor(s). GO to Pinpoint Test O.


I1 CHECK FOR AIR SPRING VENTING

Trigger VDM active commands RR SOL or LR SOL, and VENT ON.



� Does a corner lower?

Yes TRIGGER VDM active commands RR SOL or LR SOL, and VENT OFF. GO to I2 .

No TRIGGER VDM active commands RR SOL or LR SOL, and VENT OFF. GO to I4 .

I2 CHECK HEIGHT SENSOR MOUNTING POINTS

Check the height sensor mounting points.

� Are the mounting points damaged or are the height sensors disconnected from the ball studs?

Yes REPAIR as necessary. CLEAR the DTCs. CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

No GO to I3.

I3 CHECK FOR HEIGHT SENSOR OPERATION


Monitor VDM PID LR_HGT or RR_HGT.

Disconnect the selected height sensor from the lower ball stud.

Extend and compress the selected height sensor over its full range of travel.

� Does the displayed voltage for the selected height sensor vary as the length of the height sensor

changes?

Yes INSTALL a new VDM. REFER to Module — Vehicle Dynamic Module (VDM). CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

No RECONNECT height sensor(s). GO to Pinpoint Test O.

I4 CHECK FOR RESTRICTED AIR LINE

Disconnect the air line between the air compressor and the air spring that will not lower.

Connect Vacuum Tester to the air line and try to draw a vacuum.

� Can a vacuum be drawn and held?



PINPOINT TEST J: DTC C1770: AIR SUSPENSION VENT SOLENOID OUTPUT CIRCUIT FAILURE


No GO to I5.

I5 CHECK FOR RESTRICTED AIR SPRING SOLENOID VALVE

Trigger VDM active command LR SOL or RR SOL ON.

� Does air exhaust from the suspect air spring solenoid?

Yes GO to I6.

No INSTALL a new air spring solenoid; REFER to Solenoid Valve — Air Spring. CLEAR the DTCs. REPEAT the self-test.

I6 CHECK AIR COMPRESSOR AIR DRIER

Remove the air compressor air drier from the air compressor.

Blow shop air through the air drier from the air line port.

� Does air exhaust from the air drier?

Yes INSTALL a new air compressor; REFER to Air Compressor. CLEAR the DTCs. REPEAT the self-test.

No INSTALL a new air drier; REFER to Drier. CLEAR the DTCs. REPEAT the self-test.


J1 CHECK AIR COMPRESSOR ASSEMBLY CONNECTOR

Air Compressor Assembly C170

Check air compressor C170 for corrosion, bent pins and damaged wires.

� Is the air compressor C170 worn or damaged?


No GO to J2.

J2 CHECK VENT SOLENOID RESISTANCE

Measure the resistance between air compressor assembly C170F Pin 2 and Pin 3 (component side).

� Is the resistance between 19 and 24 ohms?

Yes GO to J3.

No INSTALL a new air compressor; REFER to Air Compressor. CLEAR the DTCs. REPEAT the self-test.

J3 CHECK CIRCUIT 57 (BK) FOR OPEN

Measure the resistance between air compressor C170 Pin 3, Circuit 57 (BK), harness side and ground.




Yes GO to J4.


J4 CHECK CIRCUIT 421 (PK) FOR SHORT TO POWER

VDM C408

Measure the voltage between air compressor C170 Pin 2, Circuit 421 (PK), harness side and ground.



No GO to J5.

J5 CHECK CIRCUIT 421 (PK) FOR OPEN

Connect EEC-IV 60-Pin Breakout Box to the VDM C408.

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 42, Circuit 421 (PK), and air compressor C170 Pin 2, Circuit 421 (PK) harness side.


Yes GO to J6.


J6 CHECK VDM FUNCTION

CONNECT the EEC-IV 60-Pin Breakout Box to the VDM.



PINPOINT TEST K: DTC C1773: AIR SUSPENSION VENT SOLENOID OUTPUT CIRCUIT SHORT TO GROUND

Trigger VDM active command VENT ON and then OFF while measuring the voltage between EEC-IV 60-Pin Breakout Box Pin 42, Circuit 421 (PK), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).

� Is the voltage greater than 10 volts with VENT ON and equal to zero volts with VENT OFF?

Yes TRIGGER VDM active command VENT OFF. CARRY OUT the Wiggle Test. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.

No INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CLEAR the DTCs. CARRY OUT ride height adjustment: REFER to Ride Height Adjustments. REPEAT the self-test.


K1 CHECK AIR COMPRESSOR ASSEMBLY CONNECTOR

Air Compressor Assembly C170

Check air compressor C170 for corrosion, bent Pins and damaged wires.

� Is the air compressor C170 worn or damaged?


No GO to K2.

K2 CHECK VENT SOLENOID RESISTANCE

Measure the resistance between air compressor C170F Pin 2 and Pin 3 (component side).


Yes GO to K3.


K3 CHECK VENT SOLENOID FOR SHORT TO GROUND

Measure the resistance between air compressor C170F Pin 2, component side and ground.



PINPOINT TEST L: DTCs C1790, C1795: AIR SUSPENSION LR / RR AIR SPRING SOLENOID OUTPUT CIRCUIT FAILURE

� Is the resistance greater than 10,000 ohms?

Yes GO to K4.


K4 CHECK CIRCUIT 421 (PK) FOR SHORT TO GROUND

VDM

Measure the resistance between air compressor C170 Pin 2, Circuit 421 (PK), harness side and ground.





L1 CHECK AIR SPRING SOLENOID CONNECTOR

Disconnect LR air spring solenoid C419 or RR air spring solenoid C420.

Check the suspect air spring solenoid connector for corrosion, bent pins and damaged wires.

� Is the suspect air spring solenoid connector worn or damaged?


No GO to L2.

L2 CHECK AIR SPRING SOLENOID RESISTANCE

Measure the resistance between suspect air spring solenoid pins (component side).




Yes GO to L3.


L3 CHECK CIRCUIT 57 (BK) FOR OPEN

Measure the resistance between suspect air spring solenoid (LR C419, RR C420) Pin 1, Circuit 57 (BK), harness side and ground.


Yes GO to L4.


L4 CHECK CIRCUIT 416 (LB/BK) OR CIRCUIT 429 (VT/LG) FOR SHORT TO POWER

VDM C408

Measure the voltage between air spring solenoid (LR C419 Pin 2, Circuit 429 [VT/LG] harness side; RR C420 Pin 2, Circuit 416 [LB/BK]), harness side and ground.


Yes REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

No GO to L5.

L5 CHECK CIRCUIT 416 (LB/BK) OR CIRCUIT 429 (VT/LG) FOR OPEN


If suspect air spring solenoid is LR, measure the resistance between EEC-IV 60-Pin Breakout Box Pin 41,



PINPOINT TEST M: DTCs C1793, C1798: AIR SUSPENSION LR / RR AIR SPRING SOLENOID OUTPUT CIRCUIT SHORT TO GROUND

Circuit 429 (VT/LG), and air spring solenoid C419 Pin 2, Circuit 429 (VT/LG), harness side.

If suspect air spring solenoid is RR, measure the resistance between EEC-IV 60-Pin Breakout Box Pin 38, Circuit 416 (LB/BK), and air spring solenoid C420 Pin 2, Circuit 416 (LB/BK), harness side.


Yes RECONNECT air spring solenoid. GO to L6 .

No REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

L6 CHECK VDM FUNCTION

Connect the EEC-IV 60-Pin Breakout Box to the VDM.

Trigger VDM active command LR SOL or RR SOL ON.

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin (LR 41, Circuit 429 [VT/LG] or RR 38, Circuit 416 [LB/BK]), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).

� Is the voltage greater than 10 volts with the solenoid ON and equal to zero volts with the solenoid

OFF?

Yes TRIGGER VDM active command LR SOL or RR SOL OFF. CARRY OUT the Wiggle Test. REPAIR as necessary. CLEAR the DTCs. REPEAT the self-test.



M1 CHECK AIR SPRING SOLENOID CONNECTOR

Disconnect LR air spring solenoid C419 or RR air spring solenoid C420.



Check the suspect air spring solenoid connector for corrosion, bent pins and damaged wires.

� Is the suspect air spring solenoid connector worn or damaged?


No GO to M2.

M2 CHECK AIR SPRING SOLENOID RESISTANCE

Measure the resistance between suspect air spring solenoid pins (component side).


Yes GO to M3.


M3 CHECK CIRCUIT 416 (LB/BK) OR CIRCUIT 429 (VT/LG) FOR SHORT TO GROUND

Connect the EEC-IV 60-Pin Breakout Box to the VDM C408.

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin (LR 41, Circuit 429 [VT/LG] or RR 38, Circuit 416 [LB/BK]), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).

� Is resistance greater than 10,000 ohms?

Yes RECONNECT air spring solenoid. GO to M4 .

No REPAIR Circuit in question. CLEAR the DTCs. REPEAT the self-test.

M4 CHECK VDM FUNCTION

Connect the EEC-IV 60-Pin Breakout Box to the VDM.

Trigger VDM active command LR SOL or RR SOL ON, then OFF.

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin (LR 41, Circuit 429 [VT/LG] or RR 38, Circuit 416 [LB/BK]), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).

� Is the voltage greater than 10 volts with the solenoid ON and equal to zero volts with the solenoid

OFF?



PINPOINT TEST N: DTC C1820: AIR COMPRESSOR REQUEST EXCEEDED MAXIMUM TIMING

PINPOINT TEST O: DTCs C1881, C1885, C1889, C1893: AIR SUSPENSION RF/RR/LF/LR HEIGHT SENSOR CIRCUIT FAILURE

NOTE: Make sure that the vehicle is equipped with the proper air suspension module (with or without ride control) before proceeding with test.

Yes RECONNECT air spring solenoid and CARRY OUT wiggle test. REPAIR as necessary. If no fault is found with wiggle test, INSTALL a new air spring solenoid; REFER to Solenoid Valve — Air Spring. CLEAR the DTCs. REPEAT the self-test.



N1 RETRIEVE CONTINUOUS DTCs

Retrieve and document continuous DTCs.

� Is DTC C1820 retrieved?

Yes GO to N2.

No System OK. CLEAR the DTCs. TEST the system for normal operation.

N2 CARRY OUT PNEUMATIC SELF-TEST

Allow air compressor to cool down for a minimum of 10 minutes before proceeding with this test.

Carry Out Pneumatic Self-Test

� Did the vehicle pass the Pneumatic Self-Test?

Yes System OK. Possible prior overloading of vehicle.

No GO to VDM Diagnostic Trouble Code (DTC) Index.


O1 CHECK HEIGHT SENSOR CONNECTOR

Disconnect the suspect height sensor connector as follows:

DTC Height Sensor Connector

C1881 RF C1015

C1885 RR C406

C1889 LF C1014

C1893 LR C413

Check the suspect height sensor connector for corrosion, bent pins and damaged wires.

� Is the suspect height sensor worn or damaged?

Yes REPAIR as necessary. CLEAR the DTCs.

No GO to O2.

O2 CHECK SENSOR CIRCUIT RESISTANCE


Measure the resistance between suspect height sensor Pin 2, harness side and EEC-IV 60-Pin Breakout Box pin(s) as follows:



DTC Breakout Box Test Pins Height Sensor Connector Circuit

C1881 (RF) 9 C1015 424 (TN)

C1885 (RR) 43 C406 428 (OG/

BK)

C1889 (LF) 27 C1014 422 (PK/BK)

C1893 (LR) 5 C413 427 (PK/BK)


Yes GO to O3.


O3 CHECK CIRCUIT 426 (RD/BK) FOR OPEN

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK) and suspect height sensor Pin 3, Circuit 426 (RD/BK), harness side as follows:


C1881 RF C1015

C1885 RR C406

C1889 LF C1014

C1893 LR C413


Yes GO to O4.

No REPAIR Circuit 426 (RD/BK). CLEAR the DTCs. REPEAT the self-test.

O4 CHECK FOR SHORT BETWEEN CIRCUIT 426 (RD/BK) AND CIRCUIT 432 (BK/PK)

Disconnect the wiring at all four wheel speed sensors.

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK).


Yes REPAIR Circuit 426 (RD/BK) and Circuit 432 (BK/PK). CLEAR the DTCs. REPEAT the self-test.

No GO to O5.

O5 CHECK CIRCUIT 432 (BK/PK) FOR OPEN

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK), and suspect height sensor Pin 1, Circuit 432 (BK/PK) harness side as follows:


C1881 RF C1015

C1885 RR C406

C1889 LF C1014

C1893 LR C413




Yes GO to O6.


O6 CHECK FOR SHORT TO POWER

Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB) and EEC-IV 60-Pin Breakout Box pin(s) as follows:

DTC Breakout Box Test Pins Circuit

C1881 (RF) 9 424 (TN)

C1885 (RR) 43 428 (OG/BK)

C1889 (LF) 27 422 (PK/BK)

C1893 (LR) 5 427 (PK/BK)


Yes REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.

No GO to O7.

O7 CHECK FOR SHORT TO SENSOR VOLTAGE

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 15, Circuit 426 (RD/BK), and EEC-IV 60-Pin Breakout Box pin(s) as follows:


C1881 (RF) 9 424 (TN)

C1885 (RR) 43 428 (OG/BK)

C1889 (LF) 27 422 (PK/BK)

C1893 (LR) 5 427 (PK/BK)


Yes GO to O8.


O8 CHECK HEIGHT SENSOR SUPPLY VOLTAGE


Scan Tool

Trigger VDM active command HGTPOWER ON.

Measure the voltage between suspect height sensor Pin 3, Circuit 426 (RD/BK), harness side and suspect height sensor Pin 1, Circuit 432 (BK/PK), harness side as follows:


C1881 RF C1015

C1885 RR C406

C1889 LF C1014

C1893 LR C413



PINPOINT TEST P: DTCs C1884, C1888, C1892, C1896: AIR SUSPENSION RF/RR/LF/LR HEIGHT SENSOR CIRCUIT SHORT TO GROUND

� Is the voltage between 4.8 and 5.2 volts?

Yes RECONNECT the suspect height sensor connector. GO to O9 .

No INSTALL a new VDM. REFER to Module — Vehicle Dynamic Module (VDM). CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

O9 CHECK HEIGHT SENSOR SIGNAL RANGE

Remove the suspect height sensor from the lower ball stud.

While extending and compressing the suspect height sensor, measure the voltage between EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK), and EEC-IV 60-Pin Breakout Box pin(s) as follows:


C1881 (RF) 9 424 (TN)

C1885 (RR) 43 428 (OG/BK)

C1889 (LF) 27 422 (PK/BK)

C1893 (LR) 5 427 (PK/BK)

� Does the voltage range between 0.5 and 4.5 volts as the suspect height sensor length is changed

from minimum length to maximum length?

Yes GO to O10.


O10 CHECK FOR CHANGE OF PID VALUES

From active command menu, select PID LF_HGT, RF_HGT, LR_HGT, or RR_HGT for the suspect height sensor.

Vary the length of the suspect height sensor while monitoring the PID.

� Does the PID value change as the suspect height sensor length is changed from minimum length to

maximum length?




P1 CHECK HEIGHT SENSOR CONNECTOR

Disconnect the suspect height sensor connector as follows:


C1884 RF C1015

C1888 RR C406

C1892 LF C1014

C1896 LR C413



Check the suspect height sensor connector for corrosion, bent pins and damaged wires.

� Is the suspect height sensor connector worn or damaged?


No GO to P2.

P2 CHECK FOR SHORT TO GROUND


Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB), and EEC-IV 60-Pin Breakout Box pin(s) as follows:


C1884 (RF) 9 424 (TN)

C1888 (RR) 43 428 (OG/BK)

C1892 (LF) 27 422 (PK/BK)

C1896 (LR) 5 427 (PK/BK)


Yes GO to P3.


P3 CHECK FOR SHORT TO CIRCUIT 432 (BK/PK)

Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BL/PK), and EEC-IV 60-Pin Breakout Box pin(s) as follows:


C1884 (RF) 9 424 (TN)

C1888 (RR) 43 428 (OG/BK)

C1892 (LF) 27 422 (PK/BK)

C1896 (LR) 5 427 (PK/BK)


Yes GO to P4.


P4 CHECK HEIGHT SENSOR FOR SHORT TO GROUND



Measure the voltage between EEC-IV 60-Pin breakout box Pin 46, Circuit 432 (BK/PK), and EEC-IV 60-Pin Breakout Box pin(s) as follows:


C1884 (RF) 9 424 (TN)

C1888 (RR) 43 428 (OG/BK)

C1892 (LF) 27 422 (PK/BK)

C1896 (LR) 5 427 (PK/BK)

� Is the voltage between 2.3 and 2.7 volts?



PINPOINT TEST Q: DTCs C1901, C1905, C1909, C1913: RR/LR/RF/LF SHOCK ACTUATOR CIRCUIT FAILURE

NOTE: Make sure that the vehicle is equipped with the proper air suspension module (with or without ride control) before proceeding with test.

Yes TRIGGER VDM active command HGTPOWER OFF. RECONNECT the height sensor. GO to P5 .

No INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CLEAR the DTCs. CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.

P5 CHECK FOR SENSOR SIGNAL


Measure the voltage between EEC-IV 60-Pin Breakout Box Pin 46, Circuit 432 (BK/PK), and EEC-IV 60-Pin Breakout Box pin(s) as follows:


C1884 (RF) 9 424 (TN)

C1888 (RR) 43 428 (OG/BK)

C1892 (LF) 27 422 (PK/BK)

C1896 (LR) 5 427 (PK/BK)





Q1 CHECK SHOCK ACTUATOR CONNECTOR

Disconnect the suspect shock actuator connector as follows:

DTC Shock Connector

C1901 RR C481

C1905 LR C427

C1909 RF C105

C1913 LF C1016

Check the suspect shock actuator connector for corrosion, bent pins and damaged wires.

� Is the suspect shock actuator connector worn or damaged?


No GO to Q2.

Q2 CHECK SHOCK ACTUATOR RESISTANCE

Measure the resistance between suspect shock actuator Pin 1 and Pin 3 (component side).


Yes



GO to Q3.

No INSTALL a new shock actuator; for front shock actuator, REFER to Section 204-01, for rear shock actuator, REFER to Section 204-02. CLEAR the DTCs. REPEAT the self-test.

Q3 CHECK CIRCUIT 57 (BK) FOR OPEN

Measure the resistance between suspect shock actuator connector, Circuit 57 (BK), harness side and ground as follows:

DTC Connector-Pin

C1901 C481 Pin 1

C1905 C427 Pin 1

C1909 C105 Pin 1

C1913 C1016 Pin 1


Yes GO to Q4.


Q4 CHECK CIRCUIT 843 (WH), CIRCUIT 842 (WH/OG), CIRCUIT 841 (WH/RD) OR CIRCUIT 840 (WH/BK) FOR SHORT TO POWER

VDM C408

Measure the voltage between shock actuator connector, harness side and ground as follows:

DTC Connector-Pin

C1901 C481 Pin 3

C1905 C427 Pin 3

C1909 C105 Pin 3

C1913 C1016 Pin 3


Yes REPAIR Circuit in question. CLEAR the DTCs. REPEAT the self-test.

No GO to Q5.

Q5 CHECK CIRCUIT 843 (WH), CIRCUIT 842 (WH/OG), CIRCUIT 841 (WH/RD) OR CIRCUIT 840 (WH/BK) FOR OPEN


Measure the resistance between shock actuator connector, harness side and EEC-IV 60-Pin Breakout Box pin as follows:

DTC Breakout Box Test Pin Shock Connector Pin Circuit

C1901 (RR) 52 C481 Pin 3 843 (WH)

C1905 (LR) 54 C427 Pin 3 842 (WH/OG)

C1909 (RF) 53 C105 Pin 3 841 (WH/RD)

C1913 (LF) 51 C1016 Pin 3 840 (WH/BK)


Yes



PINPOINT TEST R: DTCs C1904, C1908, C1912, C1916: RR/LR/RF/LF SHOCK ACTUATOR SHORT TO GROUND

INSTALL a new VDM; REFER to Module — Vehicle Dynamic Module (VDM). CARRY OUT ride height adjustment; REFER to Ride Height Adjustments. REPEAT the self-test.



R1 CHECK SHOCK SOLENOID CONNECTOR

Disconnect the suspect shock actuator connector as follows:

DTC Shock Connector

C1904 RR C481

C1908 LR C427

C1912 RF C105

C1916 LF C1016

Check the suspect shock actuator connector for corrosion, bent pins and damaged wires.

� Is the suspect shock actuator connector worn or damaged?


No GO to R2.

R2 CHECK SHOCK ACTUATOR RESISTANCE

Measure the resistance between suspect shock actuator Pin 1 and Pin 3 (component side).


Yes GO to R3.

No INSTALL a new shock actuator; for front shock actuator; REFER to Section 204-01, for rear shock actuator; REFER to Section 204-02. CLEAR the DTCs. REPEAT the self-test.

R3 CHECK CIRCUIT 843 (WH), CIRCUIT 482 (WH/OG), CIRCUIT 841 (WH/RD) OR CIRCUIT 840 (WH/BK) FOR SHORT TO GROUND


Measure the resistance between EEC-IV 60-Pin Breakout Box pin, and ground as follows:

DTC EEC-IV 60-Pin Breakout Box Pin Circuit

C1904 52 843 (WH)

C1908 54 842 (WH/OG)

C1912 53 841 (WH/RD)

C1916 51 840 (WH/BK)

� Is resistance greater than 10,000 ohms?


No REPAIR the circuit in question. REPEAT the self-test.



PINPOINT TEST S: DTC C1929: AIR SUSPENSION COMPRESSOR RELAY CIRCUIT FAILURE


S1 CHECK AIR COMPRESSOR RELAY CONNECTOR

Air Compressor Relay C187

Check air compressor relay C187 for corrosion, bent pins and damaged wires.

� Is the air compressor relay C187 worn or damaged?


No GO to S2.

S2 CHECK CIRCUIT 1053 (LB/PK) FOR OPEN

Measure the voltage between air compressor relay C187 Pin A, Circuit 1053 (LB/PK), harness side and ground.


Yes GO to S3.


S3 CHECK CIRCUIT 57 (BK) FOR OPEN

Measure the resistance between air compressor relay C187 Pin C, Circuit 57 (BK), harness side and ground.


Yes GO to S4.


S4 CHECK CIRCUIT 420 (DB/YE)


Measure the resistance between EEC-IV 60-Pin Breakout Box Pin 35, Circuit 420 (DB/YE), and air compressor relay C187 Pin D, Circuit 420 (DB/YE), harness side; and between EEC-IV 60-Pin Breakout Box Pin 35, Circuit 420 (DB/YE), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).



PINPOINT TEST T: DTC C1931: AIR SUSPENSION COMPRESSOR RELAY CIRCUIT SHORT TO POWER

� Is the resistance less than 5 ohms between EEC-IV 60-Pin Breakout Box and relay; and greater than

10,000 ohms between EEC-IV 60-Pin Breakout Box pins?

Yes RECONNECT air compressor relay C187. GO to S5 .

No REPAIR Circuit 420 (DB/YE). CLEAR the DTCs. REPEAT the self-test.

S5 CHECK VDM

Connect a fused jumper (60A) between EEC-IV 60-Pin Breakout Box Pin 35, Circuit 420 (DB/YE), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 57 (BK).

� Does the air compressor operate?




T1 CHECK CIRCUIT 420 (DB/YE) FOR SHORT TO POWER


VDM C408

Measure the voltage between air compressor relay C187 Pin D, Circuit 420 (DB/YE), harness side and ground.



No GO to T2.

T2 CHECK AIR COMPRESSOR RELAY

Air Compressor Relay

Connect EEC-IV 60-Pin Breakout Box.

Connect a fused jumper (60A) between EEC-IV 60-Pin Breakout Box Pin 35, Circuit 420 (DB/YE), and EEC-IV 60-Pin Breakout Box Pin 60, Circuit 875 (BK/LB).



PINPOINT TEST U: THE COMPRESSOR IS INOPERATIVE

� Does the air compressor operate?




U1 CHECK CONNECTORS


Air Compressor C170

Inspect the pins and terminals of the air compressor relay C187 and air compressor C170 for corrosion, bent or broken pins, moisture, or other damage.

� Are the connectors OK?

Yes RECONNECT the air compressor C170. GO to U2 .

No REPAIR as necessary. TEST the system for normal operation.

U2 CHECK COMPRESSOR OPERATION

Connect a fused jumper (60A) wire between air compressor relay C187 Pin A and air compressor relay C187 Pin B, harness side.

� Does the air compressor run?

Yes GO to U3.

No GO to U4.

U3 CHECK CIRCUIT 57 (BK)

Measure the resistance between air compressor relay C187 Pin C, Circuit 57 (BK), harness side and ground.




Yes INSTALL a new air compressor relay. TEST the system for normal operation.

No REPAIR the circuit. TEST the system for normal operation.

U4 CHECK CIRCUIT 1053 (LB/PK)

Measure the voltage between air compressor relay C187 Pin A, Circuit 1053 (LB/PK), harness side and ground.


Yes GO to U5.


U5 CHECK CIRCUIT 417 (VT/OG)

Air Compressor C170

Measure the resistance between air compressor relay C187 Pin B, Circuit 417 (VT/OG), harness side and air compressor C170 Pin 4, Circuit 417 (VT/OG), harness side.


Yes GO to U6.


U6 CHECK CIRCUIT 57 (BK)

Measure the resistance between air compressor C170 Pin 2, Circuit 57 (BK), harness side and ground.



PINPOINT TEST V: THE AIR SUSPENSION SYSTEM IS INOPERATIVE — ONE OR MORE CORNERS LOW, COMPRESSOR OPERATES


Yes INSTALL a new air compressor. REFER to Air Compressor. TEST the system for normal operation.



V1 CHECK FOR BLOCKED AIR LINE

Air Line at Air Drier

Air Line at LR Air Spring

Use Vacuum Tester to try to draw a vacuum on the air line at the LR air spring.

Air Line at RR Air Spring

Use Vacuum Tester to try to draw a vacuum on the air line at the RR air spring.

� Does either air line hold a vacuum?

Yes REPAIR air line as necessary. TEST the system for normal operation.

No GO to V2.

V2 CHECK FOR LEAKS IN AIR LINE

CAUTION: Do not use anything as a cap that might be drawn in to the air line.

Cap both air lines at the air springs.

Use Vacuum Tester to try to draw a vacuum on the air line at the air drier.

� Does the air line hold a vacuum?

Yes GO to V3.

No ISOLATE leak in air line. INSTALL a new air line. TEST the system for normal operation.

V3 CHECK FOR LEAKS AT AIR SPRING SOLENOID

Air Line at LR Air Spring

Air Line at RR Air Spring

Scan Tool

Connect shop air to the air line at the air drier with common fittings.

Trigger VDM active command LR SOL and RR SOL ON.

� Do both air springs inflate until full suspension travel is reached?

Yes



GO to V4.

No INSTALL a new air spring solenoid; REFER to Solenoid Valve — Air Spring. TEST the system for normal operation.

V4 LEAK TEST THE AIR COMPRESSOR ASSEMBLY

CAUTION: Do not allow the air compressor to run for more than three minutes. The air compressor could overheat and stop operating due to an internal temperature sensitive thermal breaker.

Connect an air pressure gauge with common fittings to the air line.


Connect a fused jumper (60A) wire between air compressor relay C187 Pin A, harness side and air compressor relay C187 Pin B, harness side.

Within 30 seconds, the pressure should reach 1034 kPa (150 psi).

Disconnect the jumper wire.

The pressure should hold steady.

Trigger VDM active command VENT ON.

� Did the air compressor reach and hold a minimum air pressure of 1034 kPa (150 psi)?

Yes GO to V5.

No INSTALL a new air compressor; REFER to Air Compressor. TEST the system for normal operation.

V5 CHECK THE AIR SUSPENSION HEIGHT SENSORS

Inspect the LF, RF and rear air suspension height sensor for correct installation at the upper and lower ball stud bracket and for damage.

Inspect the air suspension height sensor mounting brackets for damage.

Verify that all air lines are fully seated.

� Are the air suspension height sensor, mounting brackets and air lines OK?

Yes GO to V6.

No REPAIR as necessary. If the height sensor mounting brackets are installed or repaired, RESET front ride height. REFER to Ride Height Adjustments in this section. TEST the system for normal operation.

V6 CHECK THE AIR SUSPENSION HEIGHT SENSOR OPERATION

Turn the air suspension switch to the OFF position.

Disconnect the lower end of the LF, RF and rear air suspension height sensors.

Connect the diagnostic tool.

Monitor the LF, RF and rear height sensor PIDs.

NOTE: The voltage increases as the suspension is compressed.

While monitoring the air suspension control module LF, RF and rear height sensor PID display, slowly move the LF, RF and rear air suspension height sensors up and down their full travel.

� Do the voltages vary between 0.50 volts and 4.50 volts?

Yes RECONNECT air suspension height sensors. System is OK. TEST the system for normal operation.

No INSTALL a new height sensor. REFER to Height Sensor in this section. TEST the system for normal operation.



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