A/C Pressure Transducer

WARNING:

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

Check for Diagnostic Trouble Codes (DTC)s.
1. Turn ignition to ON (do not start engine).
2. With the scan tool, read DTCs. If either of the following DTCs are found, test the transducer and associated wiring, and repair or replace as required. Refer to STANDARD PROCEDURE .
  NOTE:
  If
  
  P0532-A/C PRESSURE SENSOR CIRCUIT LOW
  
  or
  
  P0533-A/C PRESSURE SENSOR CIRCUIT HIGH
  
  are NOT found, go to
  
  Step 2 .
Before testing the transducer function, confirm that there is a minimum refrigerant pressure in the A/C system. To confirm, connect a charging station or manifold gauge set to the refrigerant system service ports. Read the pressure on the gauges. There must be a minimum of 300 kPa (43 psi) of pressure to allow the system to operate.
- If the refrigerant pressure is less than 300 kPa (43 psi), then the system is low on charge. Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system, as required. Refer to PLUMBING, FRONT, DIAGNOSIS AND TESTING .
- If the A/C pressure is greater than 300 kPa (43 psi), verify the transducer function by performing the following steps:
  1. Turn ignition to ON (do not start engine). Read the A/C pressure on the scan tool, and compare to the reading on the charging station or manifold gauge set. The pressure readings should be within ± 50 kPa (7 psi) of each other.
    If pressures are within the above parameters, go to Step 3 .
    
    If the pressures differ by more than ± 50 kPa (7 psi), check the A/C pressure transducer wiring for high resistance which can skew the pressure signal reading. If the wiring does not have high resistance, replace the A/C pressure transducer P0532-A/C Pressure Sensor Circuit High . Refer to STANDARD PROCEDURE .
Check A/C Pressure Transducer function with A/C operating.
1. Connect a charging station or manifold gauge set to the refrigerant system service ports.
2. Start engine with A/C OFF and allow it to idle.
3. Set the A/C controls to the following positions:
  - temperature control to full cold
  - mode control to Panel / Fresh
  - blower motor control to High speed
  - A/C ON
4. Allow A/C to operate for five minutes so pressure stabilizes. Using a scan tool, read the A/C pressure, and compare to the measurement on the external gauge.
  - If the pressures are within ± 50 kPa (7 psi) of each other, the transducer is functioning correctly, and does not need to be replaced. If the A/C compressor is cycling too fast, or not cycling on at all, check the A/C system for other issues such as low system charge and issues with the evaporative temperature sensor or A/C clutch relay and wiring Intermittent Condition . Refer to STANDARD PROCEDURE .
  - If the pressures differ by more than ± 50 kPa (7 psi), check the A/C pressure transducer wiring for high resistance which can skew the pressure signal reading. If the wiring does not have high resistance, replace the A/C pressure transducer, P0532-A/C Pressure Sensor Circuit High . Refer to MODULE, POWERTRAIN CONTROL (PCM), 3.6L .