A/T - Limp Home Mode/DTC's P0750 Or P1742
37 Gearbox in limp mode operation (DTC P0750 or P1742)
37 10 12
2020488/3
10/12/2010
Supersedes Technical DIAGNOSIS AND REPAIR Group 37 number 09-13 dated September 29, 2009 for reasons listed below.
AFFECTED VEHICLES
CONDITION
^ The instrument panel indicates a gearbox problem.
^ Transmission is in limp home mode or the vehicle pulls away from a stop with delay and shudders.
^ DTC P0750 (Shift Solenoid A Malfunction) or P1742 (Clutch torque adaptation, adaptation limit reached) is logged in the transmission control
module.
TECHNICAL BACKGROUND
TCM software error.
PRODUCTION SOLUTION
Improved software version introduced.
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SERVICE
If the either TCM fault P0750 (Shift Solenoid A Malfunction) or P1742 (Clutch torque adaptation, adaptation limit reached) are stored, check the
TCM software per the software table below.
^ If necessary, update the transmission control module per the software table below and adapt the forward and reverse clutches.
Tip: If the adaptation is not possible in Guided Fault Finding due to a missing engine speed error, instructions for adapting the OAW clutches with
self-diagnosis are below.
^ If the software is already at the newer version or higher, open a TAC ticket and call the Technical Assistance Center for assistance.
SVM Update Instructions
1. Follow all instructions in the attached TSB 2011732 00 Software Version Management (SVM), operating instructions.
2. Update the transmission control unit (217) and the engine control unit using the SVM action code as listed in the table below if necessary.
3. After the SVM update, the programmed values of the clutches must be reset as follows:
a. In Guided Functions, select Transmission Electronics >> Adjustment.
After starting this function, the following question appears: Have you replaced the control unit for the automatic gearbox?"
b. Answer Yes.
Now the entry can be deleted and the adaptation of the clutches carried out.
4. Attempt the GFF clutch adaptation test plan. If the test plan fails to adapt the clutches, perform the 0AW Self-Diagnosis Clutch Adaptation
Instructions below.
0AW Self-Diagnosis Clutch Adaptation Instructions
Select the following measured values in the self-diagnosis and possibly save them under Favorites:
^ Adaptation of the forwards start-up behavior [LO] State
^ Adaptation of the backwards start-up behavior [LO] State
^ Transmission fluid temperature
^ Specified clutch torque
Creep adaptation of the forward and reverse clutch with 0AW gearboxes:
1. Make sure that there are no fault entries in the TCM.
2. Warm up the gearbox to about 85锟斤拷C, ideally by pulling away in driving mode D and R at various loads of max 1500 rpm.
Tip: Currently the adaptation is only possible when the measured value transmission temperature is between 80锟斤拷 - 95锟斤拷C.
3. When the vehicle is standing still, select driving mode D.
4. Pull away with little acceleration to about 6 mph or 10 km/h. Slowly brake the vehicle with the foot brake. Hold the brake pedal for another 5-10
seconds as the vehicle stands still.
5. When stopping, the specified clutch torque must not drop below 20 Nm, otherwise the adaptation fails. If this is the case, change the driving
profile (less load, gentler braking).
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6. Repeat step 4 until the measured value indicates the adaptation of the forwards start-up behavior is successfully completed.
7. With the vehicle standing still, select driving mode R.
8. Repeat step 4 until the measured value indicates adaptation of the backwards start-up behavior is successful completed.
When stopping, the specified clutch torque must not drop below 20 Nm, otherwise the adaptation fails. If this is the case, change the driving profile.
9. After a terminal 15 reset, the adaptation starts over again with status running. Keep the ignition switched on for at least six minutes after a
successful adaptation.
TIP: The ignition must not be switched off during this time period.
WARRANTY
ADDITIONAL INFORMATION
The following Technical DIAGNOSIS AND REPAIR will be necessary to complete this procedure:
^ TSB 2011732, 00 Software Version Management (SVM), operating Instructions.
All part and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Dept. and service manuals
for the latest information.
ATTACHMENTS
627
628
629
630
631
632
633
634
TSB 2011732, 00 Software Version Management (SVM), operating Instructions.
