P2517 indicates a low voltage condition in the AC refrigerant pressure sensor B circuit. The PCM detects that the sensor signal is below the expected minimum, suggesting an open or shorted circuit or a faulty sensor.
The sensor itself has failed electrically, providing a low or zero voltage signal to the PCM.
A broken wire, corroded connector, or loose pin in the sensor circuit can cause a low‑voltage reading.
Excessive resistance from poor contacts, corrosion, or a partially shorted wire can drop the sensor voltage below the threshold.
A poor ground connection can prevent the sensor signal from returning correctly, resulting in a low reading.
Only after confirming sensor and wiring are functional should the PCM’s AC pressure sensor input be considered faulty.
It is possible but rare. Most P2517 codes are caused by a faulty sensor, wiring, or grounding issue. Replacing the PCM should be a last resort after all sensor and circuit checks have been completed.
Clearing the code will only turn off the check engine light temporarily. If the underlying fault remains, the code will return and the AC system may continue to malfunction.
Low refrigerant can affect pressure readings but does not cause a low‑voltage circuit fault. The code specifically points to an electrical problem in the sensor circuit, not refrigerant quantity.
No. The compressor is not involved in the sensor B circuit. Replacing the compressor will not resolve a P2517 code unless a separate mechanical fault is present.