Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Symptom Chart
In most circumstances the PCM/ TCM sets a DTC to help guide with diagnostics. Refer to the DTC Chart(s) before using the Symptom Chart. The Condition column lists the vehicle condition. The Action column refers to a pinpoint test. Each pinpoint test lists the components that can cause each symptom. The components are listed in order of disassembly. Use the list of components and the directed action to identify the root cause of the concern.
| Condition | Action |
|---|---|
| Selector lever binding or difficult to move - requires excessive effort | GO to Pinpoint Test I |
| Selector lever linkage is out of correct gear relationship | GO to Pinpoint Test J |
| Brake shift interlock system does not release/lock correctly | GO to Pinpoint Test K |
| Brake shift interlock override does not release the selector lever | GO to Pinpoint Test L |
| SelectShift™ does not operate correctly | For vehicles equipped with the 6R80, GO to Pinpoint Test B For vehicles equipped with the 10R80 and a TCM, GO to Pinpoint Test D For vehicles equipped with the 10R80 and a PCM, GO to Pinpoint Test F |
| Transmission control switch does not operate correctly | For vehicles equipped with the 6R80, GO to Pinpoint Test C For vehicles equipped with the 10R80 and a TCM, GO to Pinpoint Test E For vehicles equipped with the 10R80 and a PCM, GO to Pinpoint Test G |
| Paddle shifters do not operate correctly | GO to Pinpoint Test H |
| Vibration - a high frequency (20-80 Hz) that is felt through the seat or selector lever. Changes with engine speed | GO to Pinpoint Test M |
| The ignition key cannot be turned to the OFF position, or the ignition key can be turned to the OFF position when the selector lever is not in Park | GO to Pinpoint Test N |
| The PRNDL indicator does not illuminate Park | GO to Pinpoint Test O |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.