P2522 OBD-II Trouble Code: A/C Request B Circuit

P2522 code definition

Diagnostic trouble code P2522 is defined as A/C Request B Circuit.

What the P2522 code means

When your vehicle’s computer sets this code, it means that a problem has been detected in the signal sent to the PCM (powertrain control module) from the air conditioning refrigerant pressure sensor.

Signals received by the PCM are interpreted as voltage readings in order to make it easier for the computer to detect a problem. If there are fluctuations in air conditioning system pressure, the PCM gets the message via voltage fluctuations, telling it that the system is producing either too much or too little pressure.

What causes the P2522 code?

While the most common cause of this code is low refrigerant in the A/C system, other factors can come into play as well, including:

• Excessive pressure in the system
• A faulty A/C refrigerant pressure switch or sensor (there may be up to four, depending upon make and model)
• A short or open in the system circuitry
• A bad climate control head
• A loose or damaged connector

What are the symptoms of the P2522 code?

You’ll likely see an illuminated malfunction indicator light (MIL), in addition to the stored trouble code. The most uncomfortable symptom will be that the air conditioning may not work. If the system is disabled, the A/C “ON” light, typically located on the A/C switch, may flash repeatedly.

How does a mechanic diagnose the P2522 code?

The mechanic’s diagnostic process may include:

• Reading the vehicle’s computer with an OBD-II scanner to check for any other existing trouble codes and to record freeze frame data
• Clearing out the DTCs and test driving the vehicle to see if they return (to diagnose an intermittent condition)
• Diagnosing and repairing any problems which occurred before the A/C code
• Visually inspecting the A/C pressure sensor(s) and related wiring and connectors for damage or dirty faces
• Testing voltage and ground signals at the low pressure switch connector
• Using a pressure gauge to measure the refrigerant pressure (to verify that it’s above 29 psi but below 275 to 300 psi)
• Observing the electric condenser fan during operation (if equipped)
• Checking for a refrigerant leak

Common mistakes when diagnosing the P2522 code

Refrigerant should not be added without verifying that the system is not overfilled. This can result in catastrophic system damage. The system should be thoroughly diagnosed, and both low pressure gauge and high pressure gauge readings observed to ensure the correct amount of pressure is moving through the system.

How serious is the P2522 code?

Obviously there are much more serious issues than the A/C request B circ fault. But if you live in an area with high temperatures, it could become a very uncomfortable situation very quickly. In general, however, you won’t have to worry about serious drivability or damage to vital operational components.

What repairs can fix the P2522 code?

Repairing the A/C system may involve:

• Replacing shorted, open, or damaged wiring or connectors
• Replacing the A/C refrigerant pressure sensor(s)
• Replacing the high pressure switch
• Repairing any leaks in the system
• Replacing the A/C compressor switch
• Adding refrigerant
• Replacing the climate control head

Additional comments for consideration regarding the P2522 code

Technicians recommend not attempting to use single-hose charging kits which are widely available these days. These kits do not include gauges, which can result in overfilling the system and causing even more expensive damage.

Air conditioning problems should generally be handled by a qualified mechanic who is certified to handle refrigerant according to federal laws. There are specific regulations governing the disposal of this chemical, making it wiser to simply have your vehicle repaired by a professional who has the proper tools (like A/C gauges and an A/C recycling machine) to handle the job properly.

Need help with a P2522 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.