A/C Request Circuit Range/Performance
The P255F code indicates a problem with the A/C request circuit, which is used by the powertrain control module (PCM) to monitor the A/C compressor clutch engagement request. The PCM detects that the voltage signal from the A/C request circuit is outside the expected range or not performing correctly. This can be caused by a faulty A/C pressure sensor, wiring issues, or a malfunctioning PCM. The A/C system may not operate properly, leading to reduced cooling performance.
1. Most Common Causes
- Faulty A/C pressure sensor
- Open or shorted wiring in the A/C request circuit
- Corroded or loose electrical connectors
- Malfunctioning PCM
2. Symptoms You Will Notice
- A/C compressor does not engage
- Insufficient or no cooling from A/C system
- Check Engine Light illuminated
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Visually inspect the A/C pressure sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test the A/C request circuit voltage with a multimeter; compare to manufacturer specifications.
Step 4: Check the A/C pressure sensor signal and reference voltage; replace sensor if out of range.
Step 5: If wiring and sensor are okay, test PCM output or reprogram/replace PCM as needed.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive, but the A/C system may not work properly. If the engine runs fine, you can drive, but have it diagnosed soon to avoid further issues.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on the cause. Replacing a sensor or repairing wiring is usually under $100, while PCM replacement can be more expensive.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.