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ElectricalSeverity Low: usually safe to drive

P0533A/C Refrigerant Pressure Sensor "A" Circuit High

What it means

The A/C refrigerant pressure sensor signal voltage is higher than the sensor can normally produce (close to 5 V). Most often the signal wire or the sensor ground is open, or the signal is shorted to a supply voltage.

Symptoms

  • Air conditioning not working
  • Cooling fan running at high speed

Common causes

  • Open signal wire (the ECU's pull-up then reads high)
  • Open or high-resistance sensor ground
  • Signal shorted to the 5 V reference or to battery voltage
  • Failed A/C refrigerant pressure sensor

What to check first

  1. Measure the voltage drop on the sensor ground with the key on (should be under 0.1 V)
  2. Unplug the sensor: the live data should jump to the opposite extreme
  3. Inspect the harness for chafing against other wires or hot parts
Can I drive with P0533? Usually yes. P0533 rarely affects how the car drives, but it keeps the check engine light on and can fail an emissions test.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

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P0533: questions and answers

What does P0533 mean?

P0533: A/C Refrigerant Pressure Sensor "A" Circuit High. The A/C refrigerant pressure sensor signal voltage is higher than the sensor can normally produce (close to 5 V). Most often the signal wire or the sensor ground is open, or the signal is shorted to a supply voltage.

What are the symptoms of P0533?

Air conditioning not working. Cooling fan running at high speed.

What causes P0533?

Open signal wire (the ECU's pull-up then reads high). Open or high-resistance sensor ground. Signal shorted to the 5 V reference or to battery voltage. Failed A/C refrigerant pressure sensor.

How do you diagnose P0533?

1. Measure the voltage drop on the sensor ground with the key on (should be under 0.1 V) 2. Unplug the sensor: the live data should jump to the opposite extreme 3. Inspect the harness for chafing against other wires or hot parts

Can I drive with P0533?

Usually yes. P0533 rarely affects how the car drives, but it keeps the check engine light on and can fail an emissions test.