P2523A/C Request B Circuit Low
- Generic OBD-II code · Powertrain
- How the car detects it
- P2523 reports that A/C request input B is pulled below its valid range. On the wire level this usually means a conductor grounded against body metal, a sending module whose output transistor has failed shorted, or a wet connector draining the signal. Whether the engine module then assumes a constant request or none depends on the circuit design, and no maker states it publicly; P2523 has no codegenau manufacturer documentation. The regulatory basis is CARB's A/C component monitoring, required only where the A/C changes fuel or spark control. Cars that receive the request over CAN, like the 2011 Saab 9-5, cannot set it. P2522 is the generic circuit fault on B, P2524 the high side, and P2520 the same low fault on input A. Expect missing or unwanted compressor operation.
- What you may notice
- Compressor not engaging or engaging unasked
- A/C-related idle compensation missing
- Likely causes
- LikelyInput B wire shorted to ground
- PossibleOutput stage of the sending module shorted
- RareMoisture in a connector of the request line
- Repair
- Medium · Usually a job for a workshop.Typical cost: €40 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.