Air Conditioning (A/C) Request Signal Fault
The A/C control module has detected a problem with the A/C request signal.
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 A/C system is having trouble responding to the signal that tells it to turn on or off, possibly due to a wiring issue or a bad switch.
What the computer is actually seeing
The A/C control module expects a signal from the temperature control switch indicating the A/C should be on (usually a voltage around 5V). Instead, it's seeing a low voltage, an open circuit, or a voltage that doesn't match expected patterns for a minimum of 0.5 seconds.
What a healthy reading looks like
A proper A/C request signal should be 0-5V from the switch to the A/C control module, with a typical range being a steady 5V when requested and close to 0V when not.
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 A/C control switch operation; ensure it is functioning correctly: Press the A/C button and measure the voltage at the switch. Expected is 5V or close to it.
- 22. Inspect wiring and connectors related to the A/C system for damage or corrosion. Repair as necessary.
- 33. Check the voltage at the A/C control module. Replace the switch if the signal from the switch isn't reaching it correctly.
- 44. If signals check out, test the A/C control module for faults. If necessary, replace the module.
Common causes
- Faulty A/C switch
- Wiring issues (shorts or opens)
- Bad A/C control module
- Corroded connectors
- Discharged battery affecting control signals
Typical repair cost
$$-$$$ (switch or module replacement, $100-$600)
Related codes
Frequently asked questions
Is it safe to drive with this code present?
Yes, but the A/C will not function properly. It’s best to fix it soon for comfort.
Will this code come back after I clear it?
If there is a persistent fault in the switch or wiring, it will likely return.
Why does this code sometimes pair with other codes?
It may indicate a systemic issue in the A/C system involving multiple components, like the control module or different sensors.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →