Subject: | PQC Part Restriction - Allison TCM |
Models: | 2007-2008 Chevrolet Silverado, Silverado Classic |
| 2007-2008 GMC Sierra, Sierra Classic |
| Equipped With a Allison LCT1000 (RPO MW7) Transmission |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
As of 5/8/08 the Allison Transmission Control Module (TCM) will be placed on restriction through the PQC as part of our ongoing quality improvement efforts to assist Engineering with product concern identification. Your cooperation with this program is
greatly appreciated. If diagnosis has led to replacement of the TCM please contact the PQC (866-654-7654) to discuss the information/diagnostics that led to the replacement of the TCM. Please complete the questionnaire below before calling the PQC.
Recommendation/Instructions:
- Customer Complaint (as it reads on the RO):
- Can the customer’s concern be duplicated? Y/N/Intermittent
- List all DTC's:
- Were the DTC's cleared and the vehicle test-driven? Y/N
- Did any DTC's reappear? Y/N
- SI Document ID# Used in diagnosis:
- Document each step of the trouble chart that have lead to TCM replacement. (Include all DVM readings/comments)
- Were any existing PI's or Service Bulletin's performed? If yes, please list:
- Record the Voltage to the TCM:
- Record the resistance on the TCM ground circuits:
- Was all TCM wiring checked for opens, high resistance, and shorts to grounds? (If no, perform checks)
- Is there communication between the TCM and the scan tool? Y/N
- Is there communication between the TCM and all other modules? Y/N
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.