Applicable Systems
Chevrolet
GMC
Buick
Cadillac
Symptoms
TCM internal electronic failure; transmission may default to limp mode or fail to shift.
Possible Causes
- TCM internal processor failure
- TCM software corruption
- Power supply circuit fault to TCM
Troubleshooting Steps
- Step 1: Check TCM power and ground circuits
Power and ground within specification - Step 2: Reflash TCM with latest calibration
Software update successful - Step 3: Replace TCM if internal failure persists
TCM replaced, transmission shifts normally
How to Reset
Clear codes and perform transmission relearn procedure.
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Source: SAE J2012 Standard, OBD-II Service Manuals
Category: OBD-II
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