P0890
TCM Power Relay Sense Circuit Low
Transmission / TCM power supply
Generic OBD-II
Medium
What it means
P0890 means the transmission control module reads a lower-than-expected voltage on the circuit that senses whether its power relay is on. If the module can't confirm its relay is supplying power, it may shift erratically or drop into limp mode. The engine still starts and runs — this is a transmission power-relay sensing fault, not an engine problem.
Medium
Can I keep driving? The engine starts, but the transmission may shift erratically or hold one gear — have it checked promptly.
Common symptoms
What you'll notice
- Check-engine light on
- Erratic shifting
- Transmission fails to shift or is stuck in one gear
- Transmission may enter limp mode
Common causes
Most likely first
- Faulty TCM power relayLikely
- Damaged or corroded wiring in the power relay sense circuitCommon
- Loose or corroded connectorsCommon
- Failed transmission control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the TCM power relay and its connector for corrosion or a low/open sense line.
- Check the relay sense circuit for a short to ground or high resistance with a multimeter.
- Test the relay itself for correct switching, and confirm the sense line reflects relay state.
- Replace the power relay if faulty; replace the TCM only if wiring and relay test good. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0890?+
The engine runs, but an unreliable power relay feed can cause sudden shifting problems, so limit driving until it's diagnosed.
Can I just clear P0890?+
It will clear, but the low sense-circuit reading returns until the relay or wiring is repaired.
Related codes
Often seen with P0890
Read & clear P0890 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX