P2522
A/C Request B Circuit
HVAC / A/C request signal
Generic OBD-II
Low
What it means
P2522 means the ECM has detected a fault in the "B" air-conditioning request circuit — the signal that tells the engine controller the A/C system wants the compressor to run. It's an electrical/signal fault, so the engine runs normally; the typical effect is that the air conditioning may not engage properly. Common causes are wiring problems or a faulty A/C pressure switch or HVAC module.
Low
Can I keep driving? Yes — the engine runs normally; at most the air conditioning may not engage properly.
Common symptoms
What you'll notice
- Check-engine light on
- Air conditioning may not turn on or may cycle incorrectly
- A/C compressor clutch not engaging
- No change in engine performance otherwise
Common causes
Most likely first
- Open or shorted wiring in the A/C request 'B' circuitLikely
- Faulty A/C refrigerant pressure switch/sensorCommon
- Corroded or loose connector in the request circuitCommon
- Fault in the HVAC control module or its outputLess often
- ECM/PCM input fault (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for other HVAC-related codes.
- Inspect the A/C request circuit wiring and connectors for damage or corrosion.
- Check the A/C refrigerant pressure switch/sensor and its signal to the ECM.
- Test the request circuit for continuity and for shorts to power or ground.
- Repair the wiring or replace the faulty switch/module, then clear the code and verify A/C operation.
FAQ
Quick answers
Is it safe to drive with P2522?+
Yes. This affects the air-conditioning request signal, not engine running or safety systems. The main symptom is A/C that may not work correctly.
Can I just clear P2522?+
You can, but if the wiring or A/C pressure sensor is faulty the code returns. Fix the underlying circuit first.
Related codes
Often seen with P2522
Read & clear P2522 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX