What this code means
P0533 means the PCM may be seeing the A/C pressure sensor signal higher than expected.
What the vehicle may do
- The A/C may not cool correctly.
- The A/C may be limited or disabled by system protection.
- The code can be present even if the symptom is intermittent.
Possible fault areas
- Possible A/C pressure sensor concern.
- Possible sensor connector or wiring concern.
- Possible related signal or ground circuit concern.
- Possible PCM concern after other checks are normal.
Diagnostic path
Code focus and approach
On this 2016 to 2024 Honda Civic with the 2.0 gas engine, P0533 is an A/C pressure sensor circuit high voltage code. In plain terms, the PCM is seeing the A/C pressure sensor signal higher than it expects. The driver may notice the A/C can act normally at times, or may not cool correctly if the system protects itself. Broadly, this can involve the pressure sensor signal, the sensor connection, related wiring, or in the end, the PCM. Before getting into pinpoint checks, start with the basic troubleshooting setup so the test results mean something.
Duplicate the fault
To confirm the fault, turn the vehicle to the ON mode. Turn the blower switch on, then turn the A/C switch on. On the HDS, watch A/C Pressure Sensor Voltage. If that value is more than 4.75 V, the failure is duplicated. That matches the logic for this code: when the A/C pressure sensor output voltage is higher than the specified value, the PCM judges it as abnormal and stores P0533.
Check the sensor-side result
Next, use the HDS PGM-FI Data List and monitor A/C Pressure Sensor Voltage. For the A/C pressure sensor output voltage inspection, disconnect the A/C pressure sensor 3P connector. Jump terminals No. 1 and No. 2 of that connector with a jumper wire, then turn the vehicle to the ON mode. Now confirm the HDS A/C Pressure Sensor Voltage again. A normal result here is less than 4.75 V. If it is normal during this check, the diagnostic path points to a problem with the A/C pressure sensor. If it is not normal, the path moves away from the sensor and toward the related circuit checks.
Check the PD_SENSOR and SG6 circuits
Before disconnecting the PCM connector, jump the SCS line with the HDS and wait more than 1 minute. Then prepare for the open wire checks by disconnecting the A/C pressure sensor 3P connector, PCM connector A 50P, and PCM connector E 80P. With IG Mode OFF, perform the PD_SENSOR open wire inspection. The normal condition is less than 1 Ω. Then perform the SG6 open wire inspection, also with IG Mode OFF. The normal condition is less than 1 Ω. If either of these checks is abnormal, the diagnostic direction is a problem in the circuit.
Final diagnostic call
If the sensor-side inspection and the related circuit inspections all show normal conditions, the remaining diagnostic conclusion is a problem with the PCM. The key is to keep the order clean: duplicate the high-voltage signal, use the sensor connector check to separate the sensor from the rest of the circuit, then check PD_SENSOR and SG6 for opens before calling the PCM. For more diagnostic training, visit stepdiagnostics.com.
Final check
This diagnosis is about proving whether the high signal comes from the sensor side, the related wiring, or the PCM after the circuit checks pass.
For more guided automotive diagnostics, visit STEP Diagnostics.
