Powertrain
generic / SAE
P2522
A/C Request B Circuit
General electrical fault on the second A/C request input B. Many vehicles have two HVAC zones, a rear evaporator request, or a redundant request line — input B carries that signal. With the input invalid, the ECM cannot honour zone B compressor demand or rear-evap operation.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number5 / 22
Possible causes
- Open or shorted A/C request wire B high
- HVAC module not transmitting request B medium
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 80–500 €
- Estimated time: 0.4–2 h
- Component: ac request input b
- MIL / check engine light
Sources
References
sae:J2012