P0884
TCM Power Input Signal Intermittent
Transmission control power supply
Generic OBD-II
Medium
What it means
P0884 means the transmission control module (TCM) is seeing an intermittent power-input signal — its supply voltage is cutting in and out rather than staying steady. The engine still starts and runs (the ECM has its own supply), but when the TCM loses power it can shift erratically or drop into limp mode. The usual causes are a loose or corroded power/ground connection, a flaky relay, or a weak charging system.
Medium
Can I keep driving? The engine starts, but an unstable power feed can drop the transmission into limp mode or cause erratic shifts — fix it before it strands you.
Common symptoms
What you'll notice
- Check-engine light on (may be intermittent)
- Erratic or missed shifts
- Transmission drops into limp mode
- Other transmission-related codes may be stored alongside it
Common causes
Most likely first
- Loose or corroded connections in the TCM power feedLikely
- Failed or intermittent TCM power relayCommon
- Poor TCM ground connectionCommon
- Weak battery or failing alternator causing voltage dipsLess often
- Failed transmission control module (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and note whether the fault tracks with vibration or voltage changes.
- Test battery and charging-system voltage under load to rule out supply problems.
- Inspect and clean the TCM power and ground connections; wiggle-test for dropouts.
- Check the TCM power relay and its control circuit; replace if it's intermittent.
- Repair the loose/corroded feed, then clear the code and road-test.
FAQ
Quick answers
Is it safe to drive with P0884?+
Short trips may be fine, but an intermittent power feed can put the transmission into limp mode without warning. Get the power and ground connections checked soon.
Can I just clear P0884?+
It will return whenever the power feed glitches again. Fix the loose connection, relay, or ground rather than just clearing it.
Related codes
Often seen with P0884
Read & clear P0884 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