Transmission Control Module (TCM) Power Input
This code indicates an issue with the power supply to the Transmission Control Module.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The Transmission Control Module (TCM) isn’t getting the proper power it needs to operate, likely due to a wiring or connector problem.
What the computer is actually seeing
The TCM monitors its supply voltage and expects around 12V when the vehicle is running. If the voltage drops below 10.5V for more than 3 seconds, it triggers this code.
What a healthy reading looks like
Expected supply voltage to the TCM is between 11.5V to 14.5V while running.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check the TCM power supply connector for damage or corrosion: If damaged, repair it.
- 2Measure voltage at the TCM power input with the engine running: Should be between 11.5V to 14.5V. If not, check battery and alternator.
- 3Inspect the TCM ground connection for corrosion or looseness: If it's okay, proceed to check for continuity from the TCM to the battery ground.
- 4If all checks out, consider replacing the TCM.
Common causes
- Damaged wiring or connectors to the TCM
- Faulty transmission control module
- Weak battery or alternator issues
- Poor ground connection at the TCM
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not advisable, as it can affect transmission shifting leading to drivability issues.
Will the code come back after clearing it?
Yes, if the underlying electrical issue isn't fixed.
Why does this code sometimes pair with transmission shifting problems?
The TCM needs proper power to control shifting; without it, shifting may be erratic or fail.
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