The P0533 code on your 2019 Mercedes-Benz C-Class indicates a high voltage condition in the A/C refrigerant pressure sensor circuit, typically indicating an open circuit.
High Voltage Analysis
High voltage from the pressure sensor circuit usually means the signal wire is open—disconnected or broken. The ECU sees reference voltage because the sensor isn't completing the circuit to provide a normal pressure-proportional signal.
C-Class Climate System
The 2019 C-Class features Mercedes' THERMOTRONIC or THERMATIC climate control depending on trim. Both systems require accurate pressure sensor data for safe and efficient A/C operation.
Open Circuit Causes
The sensor connector may be disconnected. Wiring between the sensor and ECU may be broken. The sensor may have failed with high internal resistance. Corroded terminals create enough resistance to read as open. A damaged harness section may have broken conductors.
Diagnostic Steps
Use Mercedes XENTRY to verify high voltage reading. Check if the sensor connector is properly connected. Test circuit continuity from sensor to ECU. Verify reference voltage reaches the sensor. If continuity is good, the sensor itself has likely failed.