B0288HVAC A/C Pressure Sensor Circuit
- Generic OBD-II code · Body
- How the car detects it
- A search found B0288 in no J2012 list and in no carmaker's service data; it stays unconfirmed. The refrigerant pressure sensor it names sits on the high-pressure line; its signal decides whether the compressor may run and how fast the cooling fan turns. On most cars the engine controller reads it and stores P0530–P0533. Saab's 9-3 with Trionic 8, for example, sets P0532 below 0.25 V and P0533 above 4.2 V, each for over 1 s with the engine running above −7 °C, and then cuts the A/C relay. Patent US9259992B2 routes the sensor to the engine module in the same way, and US5623835A uses it to drive the fan. A body code would only be used where the climate module reads the sensor itself.
- What you may notice
- Air conditioning blows warm because the compressor is disabled
- Radiator fan runs constantly or at the wrong speed
- Likely causes
- LikelyRefrigerant pressure sensor failed or signal drifting
- PossibleSensor connector near the condenser corroded by road spray
- Possible5 V reference, ground or signal wire open or shorted
- RareVery low refrigerant charge giving an implausible reading
- Repair
- Easy · Often possible to do yourself.Typical cost: €50 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.