Air Conditioning Compressor Control Circuit Low
The engine control module has detected a low voltage in the AC compressor control circuit.
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 computer is seeing a lower than normal voltage coming from the AC compressor control circuit, which means the compressor may not be getting enough power to operate properly.
What the computer is actually seeing
The ECM expects the AC compressor control circuit to have a voltage around 12V when engaged; instead, it's reading less than 6V.
What a healthy reading looks like
AC compressor control circuit voltage should be between 12V and 14V when operational, and less than 1V when off.
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 the AC system components for proper operation and fluid levels. Look for compressor engagement.
- 22. Inspect wiring and connectors between the ECM and the AC compressor. Look for frayed wires or corroded connectors.
- 33. Measure voltage at the AC compressor connector with the engine running and the AC on. It should be between 12V and 14V. If less than 6V, proceed to the next step.
- 44. Perform a continuity test on the wires from the ECM to the compressor connector. If continuity is not present, repair the wiring.
- 55. If all wiring is good, check the AC compressor for proper function. Replace if necessary.
- 66. Recheck the fault code after repairs to see if it reoccurs.
Common causes
- Wiring short to ground in the compressor circuit
- Faulty AC compressor
- Bad connector at the compressor
- ECM programming issue or failure
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's safe in the short term, but the AC won't work properly and could lead to a failure of the compressor if ignored.
Will this code come back after repair?
It shouldn't if the issue is fully corrected, but monitor for recurring symptoms.
Why does this code pair with other SPN codes?
They often indicate related issues in the AC system, so multiple SPNs can help pinpoint the problem.
Working a real vehicle right now?
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