P0885
TCM Power Relay Control Circuit/Open
Transmission controls
Generic OBD-II
Medium
What it means
P0885 means the control circuit for the transmission control module's power relay is open or not switching (TCM here is the Transmission Control Module). If the TCM can't be powered reliably, the transmission may shift erratically or fall into limp mode. The fault is usually in the relay or its wiring rather than the module. The engine still starts, though transmission behavior can be limited.
Medium
Can I keep driving? Often reduced — losing power to the transmission controller can force limp mode or erratic shifting, so get it checked soon.
Common symptoms
What you'll notice
- Check-engine light on
- Harsh, delayed, or no shifting
- Transmission drops into limp mode
- Feels stuck in one gear / reduced performance
Common causes
Most likely first
- Open in the TCM power relay control-circuit wiringLikely
- Faulty TCM power relayCommon
- Loose or corroded connections at the relay or TCMCommon
- Poor groundLess often
- Faulty transmission control module (TCM) — least likelyLess often
How to diagnose & fix
Work through it in order
- Confirm the code and locate the TCM power relay.
- Inspect the relay, its socket, and control-circuit wiring for opens or corrosion.
- Test the relay and its control signal from the TCM.
- Repair wiring or replace the relay as needed.
- If the circuit is good, have the TCM evaluated. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0885?+
The engine still starts, but the transmission may shift erratically or fall into limp mode without reliable module power. Get it checked soon.
Can I just clear P0885?+
It returns until the relay or its control wiring is repaired.
Related codes
Often seen with P0885
Read & clear P0885 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