P0880: TCM Power Input Signal — what it means, the affected system and what to check before replacing parts.
Meaning, symptoms, causes and checks
TCM power input: A fault is reported in the named circuit; the definition does not identify which component causes it. This concerns power reaching the transmission controller, not hydraulic transmission pressure. Confirm the supply circuit rather than assuming the gearbox has failed.
Affected system: Transmission controller electrical supply
Symptoms
- Irregular gear shifting or failure to shift
- Transmission stuck in limp mode
- Check Engine light illumination
- ABS or traction control system warning lights
- Vehicle sluggishness or reduced performance
Possible causes
- Blown transmission control module circuit fuse
- Defective power relay for the transmission control module
- Damaged or corroded wiring harnesses
- Faulty vehicle speed sensor
- Software glitch or internal control module failure
What to check
- Inspect all transmission and TCM related fuses for continuity
- Verify relay functionality by listening for an audible click or testing with a multimeter
- Examine wiring harnesses for physical damage, corrosion, or water ingress
- Measure power and ground supply at the TCM connector using a multimeter
- Scan for additional diagnostic codes and check manufacturer wiring diagrams
Also written as: P0880-00, P088000, PO880 (some scan tools add the fault-type byte, e.g. -00).