LCT1000 Range Inhibit or No Forward, Reverse - keywords cold dtc movement
| Subject: | LCT1000 Range Inhibit or No Forward, Reverse |
| Models: | 2001-2007 Chevrolet Silverado Classic |
| 2007-2008 Chevrolet Silverado |
| 2001-2007 GMC Sierra Classic |
| 2007-2008 GMC Sierra |
| Equipped With a Allison LCT1000 Transmission RPO M74 or MW7 |
This PI was superceded to update model years and repair instructions. Please discard PIP3413.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
No reverse and may or may not move forward after a cold start. Gear ratio DTC's may or may not be set and may or may not receive a range inhibit message.
Recommendation/Instructions:
Capture a Tech II or VDR snapshot of the concern and look at the ignition voltage during the concern
If the voltage is less then 12 volts, on Classic versions inspect circuit 1020 for the cause of the low voltage, and in new body style trucks inspect circuit 2139 for source of low voltage. If low voltage is found on the above mentioned circuits check the vehicle starting and charging system also check the ignition switch for proper operation.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
