P0533: The A/C refrigerant pressure sensor is sending a signal that is too high
A/C refrigerant pressure sensor circuit high input
Severity: Severity not verified — if the car runs badly, have it inspected
The sources describe loss of A/C operation but do not rate how urgent the code is, so no urgency is claimed here.
P0533 in short
P0533 means the A/C refrigerant pressure sensor signal is too high. TroubleCodes.net says the computer may then switch the A/C compressor off to protect the system. An overcharged system, a faulty sensor, a short in the wiring or moisture in the system are the usual causes.
The sensor reports A/C pressure to the computer. If the signal indicates very high pressure, TroubleCodes.net says the computer can disable the compressor to prevent damage.
TroubleCodes.net lists an overcharged system (for example from a top-off kit), a sensor with an internal short, a short-to-power in the wiring, and moisture that freezes and blocks the expansion valve.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Refrigerant pressure outside the normal range
Common general cause- Why it ranks here
- TroubleCodes.net lists an overcharged system first, often from a top-off kit.
- What would change this
- Rises if manifold gauges show pressure that is too low or too high. Falls if gauge pressure is normal for the ambient temperature.
Cause 2: Faulty A/C refrigerant pressure sensor
Common general cause- Why it ranks here
- TroubleCodes.net lists a defective pressure sensor as a main cause.
- What would change this
- Rises if the sensor signal is wrong with good wiring and a correct refrigerant pressure. Falls if the sensor reads correctly against gauges.
Cause 3: Damaged, corroded or disconnected wiring or connector at the sensor
Common general cause- Why it ranks here
- TroubleCodes.net lists damaged or corroded wiring and connectors among the common causes.
- What would change this
- Rises if the connector is corroded or a wire is damaged, or reference voltage or ground is missing. Falls if wiring and connector test good.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Record all stored codes and the freeze-frame data, and note whether the A/C is working at all.
IfOther A/C or sensor circuit codes are stored
It meansA shared wiring or sensor fault is more likely.
IfOnly this code is stored
It meansContinue with the wiring and sensor checks.
Step 2: Inspect the pressure sensor connector and wiring for damage or corrosion, then with the key on and engine off check for the 5 volt reference and ground at the sensor.
Warning:Back-probe gently and keep meter leads from shorting adjacent pins, which can damage the sensor circuit or the computer. Do not disconnect any refrigerant line.
IfReference voltage or ground is missing, or the connector is damaged
It meansA wiring fault is likely.
Points to: Damaged, corroded or disconnected wiring or connector at the sensor
IfWiring checks out
It meansCompare the sensor signal with the actual refrigerant pressure.
Step 3: Have a certified A/C technician measure refrigerant pressure with manifold gauges and compare it with the sensor signal voltage and the manufacturer's specification.
Warning:Refrigerant is under pressure and can cause frostbite and eye injury, and handling it legally requires certification. Leave connecting gauges and any discharging to a certified technician.
IfPressure is too high
It meansThe system may be overcharged or restricted.
IfGauge pressure is normal but the sensor signal disagrees
It meansThe sensor is suspect.
Symptoms
- A/C does not work
- Check engine light may or may not come on
- A/C indicator light on the climate controls
- Fault may reset when the engine is turned off
How to fix
On your vehicle
We don't have reviewed vehicle-specific evidence for P0533 yet. The causes and tests above apply across vehicles.
Related codes
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error