P2522: A/C Request B Circuit

What it means

The A/C request B circuit has a detected electrical fault. The code does not establish that the vehicle has a second HVAC zone or how the request is used.

At a glance

• Usually lights the check-engine light

How it works

The A/C request B circuit carries a second designated air-conditioning request signal between vehicle modules. The control module monitors that circuit and sets P2522 when it detects an electrical fault; the code does not establish whether request B serves a separate zone or what function it controls.

Common causes

Most likely first.

1. Open or shorted A/C request wire B
2. HVAC module not transmitting request B

Symptoms

• A/C operation may be unavailable or inconsistent
• A/C request B may not be recognized

How to diagnose it

1. Record freeze-frame data and check for related HVAC or module communication codes to see when the request B circuit fault occurred.
2. Compare scan-tool request B status with the available A/C controls while changing those settings.
3. Inspect the request B wire, connectors, and module terminals for an open, short, corrosion, or loose connection.
4. Using the wiring diagram, test request B wire continuity and check for shorts to ground or power with the circuit isolated as specified by the manufacturer.
5. If the circuit passes, check whether the HVAC module transmits request B and whether the receiving module detects it.

Common fixes

• Reconnect a loose request B connector or terminal.
• Clean or repair corroded request B connector pins.
• Repair an open or shorted section of request B wiring.
• Repair a faulty HVAC module or receiving-module input only after circuit tests identify it.

Can I keep driving?

You can generally drive if the vehicle otherwise operates normally, but A/C operation may be unavailable or inconsistent and request B may not be recognized. This code alone does not indicate an engine or brake fault.