P2520A/C Request A Circuit Low
- Generic OBD-II code · Powertrain
- How the car detects it
- P2520 is set when the voltage on A/C request input A stays below the band the engine module accepts. Depending on whether the input is active-high or active-low, a grounded wire then reads as a permanent request or as none at all – either way the module distrusts it. Most often a harness rubbed through to body metal, a pinched wire behind the dashboard or a climate panel output stuck low is behind it. No maker publishes P2520 with thresholds; CARB only requires that A/C parts influencing fuel or spark control be checked, and on many cars with a networked request such as the 2011 Saab 9-5 the wired input does not exist. Unlike P2519 the circuit is not simply open, and P2521 is its high counterpart. The A/C may refuse to run or run unasked.
- What you may notice
- A/C does not switch on, or compressor runs although A/C is off
- Idle speed behaves oddly when the A/C is toggled
- Likely causes
- LikelyRequest wire shorted to ground
- PossibleClimate control output stuck low
- RareEngine module input stage faulty
- 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.