P0533A/C Refrigerant Pressure Sensor A Circuit High
- Generic OBD-II code · Powertrain
- Matters for the ITP
- How the car detects it
- The engine module reads the high-side refrigerant pressure sensor (5 V reference, signal rising with pressure) to switch or regulate the compressor, raise the radiator fans at high pressure and pre-control the compressor load at idle. CARB therefore requires A/C components to be monitored where they alter fuel or ignition control or feed other diagnoses (from 2006–2008). P0533 means the signal voltage is too high – GM above 98 % of the 5 V reference in 80 of 100 samples, from a signal shorted to positive or an open sensor ground. Real very high pressure normally leads to a pressure cut-out within range instead. The compressor is locked out. Warning lamp: GM type C without, Saab 9-4X with, Ford depending on vehicle.
- What you may notice
- Air conditioning not cooling (compressor off)
- Radiator fan running permanently
- Check engine light (depending on the maker)
- Likely causes
- LikelySignal line shorted to positive (e.g. 5 V reference)
- LikelySensor ground open
- PossiblePressure sensor faulty internally
- RareExtreme overpressure (overcharge, blocked condenser, fan off)
- Inspection (ITP)
- Can matter for the ITP: it concerns the emissions system.
- Repair
- Easy · Often possible to do yourself.Typical cost: €40 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.