P256F Possible Causes
- Low refrigerant
- Excessive refrigerant
- Faulty low pressure sensor
- Low pressure sensor side harness is open or short-circuited
- Poor electrical connection in the low pressure sensor circuit
How to Fix P256F Code
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
Check Engine Light illuminated (or Service Engine Soon warning light)
P256F Meaning
The Powertrain Control Module (PCM) monitors refrigerant pressure through the Air Conditioning (A/C) pressure sensor. The PCM provides a 5V reference and a low reference to the sensor. Changes in A/C refrigerant pressure cause the sensor’s signal to the PCM to vary. When pressure is high, the signal is high. When pressure is low, the signal is low. The PCM sets the OBDII code when the sensor signal falls outside factory specifications.