P0533 code meaning
A/C Refrigerant Pressure Sensor A Circuit High
What P0533 means
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.
P0533 at a glance
- Check engine lightUsually not
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0533
- Air conditioning not cooling (compressor off)
- Radiator fan running permanently
- Check engine light (depending on the maker)
Common causes of P0533
- Most likelySignal line shorted to positive (e.g. 5 V reference)
- Most likelySensor ground open
- PossiblePressure sensor faulty internally
- Less likelyExtreme overpressure (overcharge, blocked condenser, fan off)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Ac refrigerant pressure sensorSensor wiringEngine control module
What each part of P0533 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5 | Area: vehicle speed, idle control and auxiliary inputs. |
| 33 | The exact fault in that area. |
What to do next
- Note P0533 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0533
What does P0533 mean?
P0533 means "A/C Refrigerant Pressure Sensor A Circuit High". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0533?
P0533 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will P0533 fail an emissions test?
Yes, it can. P0533 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0533 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0533 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.