What Does P255F Mean?
The PCM has detected an abnormal signal from the air conditioning request circuit. The voltage or signal pattern from the A/C control module or switch does not match expected parameters for proper A/C system operation.
Common Causes
30%
Faulty A/C pressure switch sending incorrect signal
25%
A/C control module internal fault or communication error
25%
Damaged wiring or poor connection in A/C request circuit
15%
Faulty A/C clutch relay affecting signal feedback
5%
Low refrigerant causing abnormal pressure readings
Diagnostic Steps
1
Step 1: Check A/C system operation and verify compressor clutch engagement
2
Step 2: Scan A/C control module for additional codes and monitor live data
3
Step 3: Test A/C pressure switch operation and signal voltage at PCM
4
Step 4: Inspect wiring between A/C control module and PCM for damage
5
Step 5: Verify A/C clutch relay operation and check for proper voltage supply
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
The PCM has detected an abnormal signal from the air conditioning request circuit. The voltage or signal pattern from the A/C control module or switch does not match expected parameters for proper A/C system operation.
The most common cause of P255F (A/C Request "A" Circuit Range/Performance) is: Faulty A/C pressure switch sending incorrect signal
Typical repair costs for P255F range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
No direct safety concern. A/C system may not function properly but vehicle is safe to drive.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P255F to identify the root cause.
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Quick Info
Category
Powertrain
System
Air Conditioning System
Difficulty
Type
Generic (SAE)
Recommended Tools
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