P0861
PowertrainModule Communicationhigh severityGear Shift Module Communication Circuit Low
What P0861 Means
The signal voltage on the gear shift module communication circuit is lower than expected. This often points to a short to ground or an open in the wiring.
Symptoms
- Erratic or no gear position indication
- Shifting problems or no shift
- Transmission warning light
Common Causes
- Short to ground in communication wiring
- Damaged connector or corroded pins
- Faulty gear shift module
- Failed transmission control module
Diagnostic Steps
- Retrieve all stored codes
- Inspect wiring for shorts to ground
- Measure circuit voltage and compare to spec
- Repair wiring or replace gear shift module as needed
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