P0862 Gear Shift Module Communication Circuit High

P0862 points to a high gear shift module communication circuit. The communication path is above range, open, or shorted to voltage.

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 condemn the transmission controller until the high communication circuit fault is isolated.

Symptoms of P0862

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 P0862

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

Measure communication circuit voltage, check for short-to-voltage faults, open grounds, connector corrosion, and module power issues.
Confirm shifter module presence on the network and compare gear selector data with the instrument cluster and transmission controller.
Inspect recent console work, water entry, spilled liquids, or wiring repairs that could affect the shifter communication circuit.

Related OBD-II codes

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