Powertrain
generic / SAE
P0887
TCM Power Relay Control Circuit High
The TCM power relay reports a control circuit high condition. TCM supply control is impaired. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number8 / 87
Possible causes
- Control wire shorted to B+ high
- Open relay coil medium
- Connector pins corroded - high contact resistance low
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 120–600 €
- Estimated time: 0.5–3 h
- Component: tcm power relay
- Component: wiring harness
- Component: tcm
- MIL / check engine light
- limp mode possible
Sources
References
sae:J2012