24 Transmission Digest

01J CVT: Diagnosing and Repairing Code 17090

A2003 Audi A4 with an 01Jcontinuously variable trans-mission (CVT) came to our

shop. The customer complainedthat the vehicle was sluggish in for-ward and had no reverse and thatthis would take place only when allthe lights in the gear indicator“lighted up and flashed.”

CVTs are starting to show up inour shops, so we have to be pre-pared to diagnose and repair theseunits. To do so we have to under-stand how they are designed towork. Wayne Colonna has writtena number of articles on this trans-mission that have appeared inTransmission Digest, such as “TheBucking Audi” in April 2007. Healso provided excellent informa-tion in ATSG’s 2008 and 2010 semi-nars. All this information isrecommended reading if you’replanning to do repairs on thistransmission.

Let’s start by explaining howcodes are stored in the 01J CVT.Audi has categorized transmissioncodes in three categories. First arethe non-critical-state codes. In thisstate a fault code is stored and thetransmission control module(TCM) will substitute a program toenable continued operation of thevehicle with some restrictions.Since this state is not critical, it’snot indicated to the driver (Figure1), although the driver may notice

the fault by the different way thevehicle is operating.

The second state we can callnon-critical, but with restrictions.In this state the TCM stores thecode and substitutes a program toenable continued operation, but

with some restrictions, and theTCM informs the driver by invert-ing the display of the gear-selector-position indicator (Figure 2).

The third state we can call thecritical state. In this state the TCMstores the code and substitutes aprogram for continued operationwith restrictions, at least until thevehicle comes to a stop. Then it willput the vehicle into a failsafe stateand inform the driver by invertingthe gear-selector-position indicatorand causing it to flash (Figure 3). Inthis state, in some instances the ve-hicle will not be drivable but inothers the driver can resume opera-tion of the vehicle by restarting it.

When we scanned the vehicle forcodes, we obtained code 17090“Transmission Range Sensor(F125)” (Figure 4), but since the

4

Subject: Code 17090

Unit: 01J CVT

Vehicle Applications: Audi A4

Authors:Jesse Zacarias & Roy Delfran

Essential Reading: Rebuilder

Shop Owner

Center Manager

Diagnostician

R & R

Shift PointersT

EC

HN

ICA

LT

RA

ININ

G

3

2

1

Non-critical state

Non-critical with restrictions

Critical state and failsafe

Category 3 – codes stored; display inverted and flashing

Category 1 – codes stored; no display change

Category 2 – codes stored; display inverted

continues page 26

26 Transmission Digest

Shift Pointers

malfunction was intermittent wecould not detect the problem ofwhich the customer was complain-ing.

After a couple of road tests theproblem the customer had com-plained of appeared and the gear-selector-indicator lights wereinverted and flashing, telling usthere was a critical-state code.

The transmission multi-functionrange sensor (F125) provides alogic state that informs the TCM ofthe gear selected. The sensor iscomposed of four Hall-effect sen-sors that are controlled by the mag-netic gate on the selector shaft andcan produce both high and lowvoltage readings. A high voltagereading means the switch is closedand is given a value of “1.” A lowvoltage reading means the switch isopen and is given a value of “0.”Thus, a Hall-effect sensor can gen-erate two signals: 1 and 0. Thesefour sensors can produce 16 differ-ent gearshift combinations: four forthe gear selected (P, R, N and D);two for intermediate positions (P-Rand R-N-D); and 10 combinationsthat are considered faulty (Figure5). One thing worth mentioninghere: If Hall-effect sensor D fails,

starting the vehicle may not be pos-sible.

By using the data parameters(see example in Figure 6) wechecked the logic state of the trans-mission range sensor and found itto be in the fault state.

Since the range sensor is part ofthe TCM, we had to remove theTCM from the valve body (Figure7).

We had three options. We couldbuy a new TCM from the Audidealer or buy a used one, either ofwhich would require sending thevehicle to the Audi dealer to pro-

6Gear-

selector-leverposition

Hall-effect sensor states

A B C D

P 0 1 0 1Between P & R 0 1 0 0R 0 1 1 0Between R & N 0 0 1 0N 0 0 1 1Between N & D 0 0 1 0D 1 0 1 0

Faulty logic combinations

0 0 0 00 0 0 10 1 1 11 0 0 01 0 0 11 0 1 11 1 0 01 1 0 11 1 1 01 1 1 1

5

Using a scan tool to see the status of the multi-function sensor

7

The TCM is fastened to the valve body with three bolts.

8

When you remove the spring tensionfrom the detent and remove it fromthe selector shaft, be careful not tolose the small wheel in it, as it canfall off easily.

March 2010 27

gram the TCM to the vehicle and toreset the adaptations. The third op-tion was to have the vehicle’s ownTCM rebuilt. This option wouldnot require sending the vehicle tothe dealer for reprogramming be-cause it was the original TCM.

So we sent the vehicle’s TCM toBBA-REMAN to have it rebuilt,and it took only four days roundtrip. By going to the company’sWeb site, www.bba-reman.com, wewere able to handle everything on-line, including printing a UPS calltag. One piece of advice here: Onceyou are on the Web site, make sureyou click on the right flag for thecountry you are in. You also can ac-complish the transaction by phone.

When we removed the TCM wechecked for metal particles on theselector-shaft magnetic gate(Figure 9). These metal particlescan cause false readings by excitingthe Hall-effect sensors; however,we did not find any indication ofthat on this vehicle, so the problemhad to be inside the TCM.

When we received the rebuiltTCM we installed it and replacedthe seal, gasket and rear-coverbolts. According to Audi these arestretch bolts that are made to beused only once.

To fill with CVT special fluid#G-052-180-A2, we used a Hondapower-steering pump that is drivenby the speedometer, together witha drill (Figure 10). After we road-tested the vehicle, the fluid levelhad to be checked with the fluidtemperature at 35°-45° Celsius(Figure 11).

This repair was not complicated;it was in our opinion an easy fix,and the satisfaction of seeing thesmile on the customer’s face, wheneveryone else wanted to sell him anew transmission, was, as they sayin the credit-card commercial,“priceless.”

Jesse Zacarias is the owner of Elec-TranDiagnostics in Gilroy, Calif. Roy Delfran is withSnap-on Diagnostics “Ask-a-Tech Web Services”(http://askatech.snapon.com).

TD

11

10

9

Checking for metal particles on the selector-shaft magnetic gate