4X4 System - Inoperative/AWD/4WD Lamps ON
TSB SB04-05-S010Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD
System (This Bulletin Supersedes SB04-05-5002)
ISSUE DATE: JULY 2004
Affected Vehicles
2003-2004 Isuzu Ascender (US/UT) models equipped with Electronic Shift or Active Transfer Case (RPOs NP1 NP4 or NP8).
Service Information
This bulletin is being revised to update Step 5 of the service procedure and supersedes bulletin 5B04-05-5002.
Condition:
Some customers may comment that the 4WD/AWD indicator lights on the selector switch do not work, or the 4WD/AWD system may be inoperative and/or the service 4WD light is illuminated. The condition is typically intermittent and always occurs at key-up.
Possible Cause:
The Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode".
When the TCCM is in the "sleep mode", it will not communicate with the class II bus or the Tech 2.
Correction:
Reprogram the Transfer Case Control Module.
Service Procedure
1. Try to communicate with the TCCM. If no communication is established, go to step 2. If communication is established, go to step 5.
2. Remove the underhood (ATCM or TREC) TCCM fuse.
3. Wait 30 seconds.
4. Reinstall the fuse. The module should "wake up" and communicate with the Tech 2.
5. Check for codes in the TCCM. If a COSSO is found current or in history with or without other codes, replace the module and go to step 6.
6. Reprogram the TCCM using normal SPS procedures, using ITCS software version 30 or later.
7. Verify operation and that no codes are present.
Warranty Claim Information
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