CUMMINS ENGINE

INFORMATION

Onboard Diagnostics - QSL Tier III Engines

5.2.2.1 Fault Detection: Faults are detected while the key switch is on, during the oper-ation of the machine itself. If a fault becomes active (currently detected) at this time, afault is logged in memory and asnapshot of engine parameters is logged. In addition, cer-tain faults may illuminate the warning lamp (amber) or the stop lamp (red). 1. Flash Out of Fault Codes: Fault flash out mode can be entered through the use of a diagnostic switch or the accelerator pedal. The diagnostic switch may also be multi-plexed on the J1939 datalink.The Service Brake switch may be multiplexed and its value obtained through the J1939 datalink (Refer to Section 2.9.1 Multiplexing). To enter the fault flash out the key switch must be on with the engine not running. When a diagnostic switch is used to enter the mode, the ECM will automatically flash the first fault code after the switch is turned on. The diagnostic increment/ decrement is used to sequence forward or backwards through the active faults.

Figure 5.1 Example Fault Code Sequences

2. Fault Lamps: The CM850 controller systems use up to three indicator lamps: the stop lamp, the warning lamp, (these two being mandatory) and a wait-to-start lamp. If the key switch is turned on but the diagnostic switch remains off, the indicator lamps will illumi-nate for approximately two seconds and then go off, one after the other, to verify they are working and wired correctly. See illustration below where they are all on and then go off one at a time, at an interval of 0.5 seconds each.

Figure 5.2 Fault Lamp Sequencel

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*Warning Lamp - The warning lamp provides important operator messages. These mes-sages require timely operator attention. The warning lamp is also used to delineate diag-nostics fault codes.

*Stop Lamp - The stop lamp provides critical operator messages. These messages require immediate and decisive operator response. The stop lamp is also used to flash out diagnostic fault codes. It is possible, through OEM wiring, to configure the system to use the red/stop lamp for engine protection faults. This is done through wiring the red lamp to both the red/stop lamp input and the engine protection lamp input on the ECM.

* Wait-to-Start Lamp - The wait-to-start lamp indicates that the pre-start intake manifold heater warm-up sequence is active. An OEM-supplied grid heater will automatically heat the intake manifold when needed prior to engine starting. Intake manifold heating improves engine starting in cold temperatures and reduces white smoke.

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SAE Diagnostic Trouble Codes and Cummins Fault Codes

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