OBD-II code · Powertrain (generic)
P0891 TCM Power Relay Sense Circuit High
The TCM detects voltage on the relay sense line above threshold while relay is commanded open, indicating relay welded closed or short to power.
Is it safe to drive with P0891?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyRelay contacts welded
- PossibleWiring shorted to battery
- Less likelyConnector pins corroded - high contact resistance
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
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Tcm Relay, Wiring Harness
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.