Engine Controls - MIL ON/DTC 23 (Gearbox Fault)
No: 19/09/97/NASRef: WSM Section 19
*Issue: 2*
Date: 12/05/97
PRIDE V 1-19
MIL Illumination
Gearbox Fault Code 23
AFFECTED VEHICLE RANGE:
RANGE ROVER (LP) 1995-1997
* indicates updated information
SITUATION:
FALSE MIL ILLUMINATION IN COLD AMBIENT TEMPERATURES
There have been some cases in which customers have complained of a MIL illumination during low ambient temperature operation. Code retrieval reveals a DTC P1775 and a gearbox fault 23. The problem is more prevalent on 4.6L vehicles under hard acceleration. In some cases the gearbox will default to 3rd gear when the fault is present.
RESOLUTION:
REPLACE PROM IN GEMS ECM
In order to properly diagnose this fault the technician should retrieve P-Codes and Freeze Frame data and FAX a completed DTCR to LRNA. A new PROM has been developed which will eliminate this problem for each affected model year. Use the following procedure to diagnose and repair this condition.
NOTE:
The repairs outlined in this TIB are to be performed to resolve customer complaint of the symptoms described.
PARTS INFORMATION:
PRM9638 PROM MY 1995
PRM9636 PROM MY 1996
PRM9639 PROM MY 1997
LRNASTATK Anti-Static Mat
NOTE:
PROM sets will only be released with the approval of the GEMS Helpline.
WARRANTY CLAIMS:
*19.22.96 Time 1.05 hrs.
TestBook hookup, access codes, complete DTCR and
diagnostic drive cycle "C" per Service bulletin W97-007*
18.30.89/26 Time 0.50 hr
Replace PROM set
19.22.17.75 Time 0.05 hr
GEMS P-Code P1775
44.90.21 Time 0.05 hr
Transmission Code Diagnosis
COMP CODE: 6U5A
Normal warranty policy and procedures apply
REPAIR PROCEDURE:
TESTBOOK
1. Hook up TestBook and follow directions to retrieve fault codes.
2. Follow basic diagnostic directions as specified by TestBook.
3. Complete a DTCR, including freeze frame data.
4. If TestBook tests do not resolve the problem, follow the procedures below.
CHECK ENGINE SETTINGS
1. With TestBook, go to GEMS Real Time Monitoring and observe Ignition Retard PWM signal. A fully warm engine should read approximately 17%.
2. A reading of 13% indicates a hard fault. If a hard fault is present, it must be repaired before continuing with this procedure.
3. Go to Gearbox Real Time Monitoring and observe the torque value input to the gearbox TCM.
4. If no problems are noted with these measurements, FAX the completed DTCR to the GEMS Helpline for authorization of PROM replacement.
5. Install the updated PROM set, reset the ECM adaptations and IACV steps to 20-25.
6. Perform Drive Cycle "C".