A/C Request B Circuit
The P2522 code means the vehicle's onboard diagnostic system has detected: A/C Request B Circuit. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- $100 - $450 (parts and labor)
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Common Symptoms
- Rear A/C not functioning
- Dual-zone climate control issues
- Check engine light on
- Front A/C works but rear does not
Probable Causes (Ranked by Likelihood)
- Faulty rear A/C request switch or module Very High
- Open circuit in B request wiring High
- Failed rear climate control module Moderate
- ECM B circuit input fault Low
Frequently Asked Questions
What is the A/C Request B circuit?
On vehicles with dual-zone or rear A/C systems, the B circuit handles the secondary A/C request, typically from the rear climate control.
Why does only my front A/C work?
P2522 indicates the rear A/C request signal is not reaching the ECM, so the rear system cannot request compressor operation independently.
Is P2522 common on minivans and SUVs?
Yes. Vehicles with rear A/C systems have additional wiring running to the back of the vehicle, which is more susceptible to damage and connection issues.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Test rear A/C request switch operation
-
Check B circuit wiring for continuity from rear module to ECM
-
Inspect rear climate control module connectors
-
Verify ECM receives B request signal with scan tool
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Commonly Affected Vehicles
- 2010-2020 Toyota Sienna
- 2012-2019 Honda Odyssey
- 2008-2018 Ford Expedition
- 2011-2020 Chevrolet Suburban
Related Codes
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