P0886 TCM Power Relay Control Circuit Low

P0886 indicates a low TCM power relay control circuit condition. The relay-control voltage or driver response is lower than expected.

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 transmission solenoids for a relay-control fault; stabilize TCM power control first.

Symptoms of P0886

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 P0886

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

Check for short-to-ground, low relay coil resistance, damaged insulation, relay socket corrosion, and control-driver behavior.
Compare command state with voltage at the relay coil and output feed to the TCM.
Inspect shared fuse feeds and grounds if other relay or module-power codes are present.

Related OBD-II codes

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