Transmission Control System Voltage Low
This code indicates low voltage in the transmission control system.
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) needs a certain voltage to work properly; when it drops too low, it can't control the transmission as needed.
What the computer is actually seeing
The Transmission Control Module expects a voltage between 10-16 volts. If it sees less than 10 volts for a certain period (like 2 seconds), it triggers this code.
What a healthy reading looks like
Voltage should read between 10-16 volts at the TCM power supply pin.
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.
- 11. Check battery voltage. It should be between 12.4 and 12.8 volts at rest. If voltage is low, charge battery and retest.
- 22. Inspect the wiring and connectors going to the TCM for damage or corrosion. Repair any faults found.
- 33. Check ground connections related to the TCM. Voltage drop should not exceed 0.1 volts. Repair poor grounds if necessary.
- 44. If wiring and battery are fine, use a scanner to check TCM operation. See if it responds to inputs (like gear selection) appropriately.
- 55. If the TCM is unresponsive and all other checks are good, consider replacing the TCM.
Common causes
- Corroded or damaged wiring to the TCM
- Faulty TCM
- Weak battery or charging issues
- Poor ground connections
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive long distances as this could lead to transmission shifting issues.
Will this code come back after resetting?
If the underlying issue isn't fixed, the code will likely return.
Why might this code appear with shifting problems?
If the TCM is not getting enough voltage, it can't control the transmission properly, leading to erratic shifting.
Working a real vehicle right now?
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