P0891: TCM Power Relay Sense Circuit High
MediumPowertrainTransmission
What does P0891 mean?
P0891 is a diagnostic trouble code indicating "TCM Power Relay Sense Circuit High". The ECU is reading a voltage that is above the expected range. This can be caused by a short to power in the wiring, a failed sensor, or a connector issue in the transmission.
Symptoms you may notice
- Check engine light (MIL) illuminated on dashboard
- Intermittent warning lights
- Erratic gauge readings
Estimated repair cost
Typical range in Australia (parts + labour)
$100 – $500 AUD
Common causes
- Damaged or corroded wiring harness
- Loose or disconnected electrical connector
- Failed transmission sensor or actuator
- Blown fuse in the related circuit
- Poor ground connection
What should you do?
This code sits in a powertrain control module. The engine or transmission can drop into limp mode or cut out, which is its own hazard in traffic or on a motorway. Get it diagnosed before your next trip rather than waiting for the next service.
Get a diagnosis for YOUR car
Code P0891 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.