P0887 TCM Power Relay Control Circuit High

P0887 indicates a high TCM power relay control circuit condition. The relay-control circuit is higher than expected or stuck high.

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 TCM before proving the relay-control circuit is not shorted or stuck powered.

Symptoms of P0887

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 P0887

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-voltage, open control ground, relay socket faults, connector damage, and driver-circuit issues.
Compare relay command with actual coil voltage and TCM power output when the relay should be off and on.
Inspect recent wiring repairs, aftermarket electronics, and water intrusion near relay or fuse panels.

Related OBD-II codes

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