Powertrain, generic (extended)

P2522 A/C Request B Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2522 is the general circuit code for a second wired A/C request input, B. Why an engine module would need two such lines is left to each maker; plausible uses are a separate rear evaporator, a second request stage or a redundant line to cross-check input A. The common purpose stays the same: the module must learn of the coming compressor load in time to adjust idle and torque. CARB has required monitoring of electronic A/C components since the 2006–2008 phase-in, provided switching the A/C alters fuel or spark control. In networked systems, such as the 2011 Saab 9-5 that receives its A/C request as a CAN message, no such wire exists. No maker documents P2522 publicly. P2523 and P2524 denote low and high levels on B, P2519 the fault on input A.

Likely causes

Input B wire broken or connector loose
Sending climate module or switch faulty
Engine module input stage faulty

Symptoms

  • A/C function served by input B unavailable
  • Idle dips when the compressor engages without notice

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€40–400
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

ac request input bhvac module

Related codes

P2523P2524P2519

References: law.cornell.edu, saabwisonline.com.