P0860 Gear Shift Module Communication Circuit

P0860 points to a gear shift module communication circuit fault. The controller cannot communicate reliably with the shifter or gear selector module.

Code details

Generic OBD-II · P0

System: Transmission
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the shifter module until power, ground, and network integrity have been tested.

Symptoms of P0860

Harsh, delayed, or slipping shifts, or being stuck in one gear.
Check-engine light, sometimes with limp-home mode.
Flaring RPM or a shudder under load.

Common causes of P0860

Low or degraded transmission fluid.
A failing speed sensor, shift solenoid, or pressure-control circuit.
Wiring, connector, or internal hydraulic/mechanical faults.

Useful checks before replacing parts

Scan all modules for communication codes and check whether the gear shift module is online and reporting selector data.
Inspect shifter module power, grounds, network wiring, connector fit, water intrusion, and console wiring strain points.
Compare range, gear display, shift-lock, manual-mode, and start-inhibit behavior with communication status.

Related OBD-II codes

These nearby transmission entries can help compare wording and pin down the fault area.