Powertrain
generic / SAE
P2521
A/C Request A Circuit High
The A/C request input A reads stuck high — typically a short to battery voltage. The ECM cannot pull the line low to read switch state, so the A/C compressor request is treated as invalid and the clutch stays disengaged.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 21
Possible causes
- Request wire shorted to battery voltage high
- Connector pins corroded - high contact resistance low
- Supply wire pinched against B+ source low
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 80–500 €
- Estimated time: 0.4–2 h
- Component: ac request input a
- MIL / check engine light
Sources
References
sae:J2012