Diagnostic trouble code (DTC) information

Condition

Fig 1: Identifying A/C Pressure Sensor

Courtesy of VOLVO CARS OF NORTH AMERICA.

The control module checks the compressor clutch thermal switch, although only once per operating cycle or 15 minutes after the last compressor activation.

The control module also checks that the pressure rises 61 kPa within 12 seconds at the first compression stroke otherwise the control module interprets it as a faulty signal.

In addition the A/C pressure sensor checks that the outside temperature is above 15 °C, the speed above 50 km/h and the pressure lower than 97 kPa for more than 4 minutes. If these conditions are satisfied the control module interprets it as a fault, no signal, and diagnostic trouble code (DTC) ECM-500A is stored.

Substitute Value

Air conditioning (A/C) shut off
A/C pressure of 700 kPa assumed

Possible Source

Faulty signal:

defective air conditioning (A/C) compressor
low pressure in the air conditioning (A/C) system

No signal:

low pressure in the air conditioning (A/C) system
defective air conditioning (A/C) pressure sensor

Fault symptom[s]

Air conditioning (A/C) compressor not operating