P0532
DTC P0532 A/C REFRIGERANT PRESSURE SENSOR "A" CIRCUIT LOW INPUTComponent Location:
GENERAL DESCRIPTION
The ECM (Engine Control Module) receives pressure signal in the A/C refrigerant high pressure side from the A/C refrigerant pressure sensor. This input indicates how much load the A/C compressor is putting on the engine and is one of the factors used by the ECM in order to determine the idle air control position for the idle speed. The circuits consist of a 5 V reference and a ground, both provided by the ECM, and a signal from the sensor. The signal is a voltage which is proportional to the A/C pressure from 0 to 5 V. Low pressure produces a low voltage signal and high pressure a high-voltage signal.
DTC DESCRIPTION
ECM sets DTC P0532 if the ECM detects signal voltage lower than the possible range of a properly operating A/C refrigerant pressure sensor.
DTC Detecting Condition:
Schematic Diagram:
Signal Waveform And Data Part 1:
Signal Waveform And Data Part 2:
MONITOR DTC STATUS
NOTE: If any codes relating to Power Steering Pressure Sensor(P0552, P0553) or Fuel Tank Pressure Sensor(P0452, P0453) are present, Check for open/short circuit in power supply circuit(ECM terminal 48) and repair as necessary before proceeding with this troubleshooting tree.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Read "DTC Status" parameter.
5. Is parameter displayed "History (Not Present) fault"?
NOTE:
- History (Not Present) fault : DTC occurred but has been cleared.
- Present fault : DTC is occurring at present time.
YES - Fault is intermittent, caused by poor contact in the sensor's and/or ECM's connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below
POWER CIRCUIT INSPECTION
1. Ignition "OFF".
2. Disconnect A/C pressure sensor connector.
3. Ignition "ON" & Engine "OFF".
4. Measure voltage between terminal 3 of the A/C pressure sensor harness connector and chassis ground.
Specification : Approx. 5 V
5. Is voltage within the specification?
YES - Go to next step as below.
NO - Repair as necessary and go to "Verification of Vehicle Repair" procedure
GROUND CIRCUIT INSPECTION
1. Ignition "OFF".
2. Measure resistance between terminal 1 of the A/C pressure sensor harness connector and chassis ground.
Specification : Approx. 0 ohm
3. Is resistance within the specification?
YES - Go to next step as below.
NO - Repair as necessary and go to "Verification of Vehicle Repair" procedure
SIGNAL CIRCUIT INSPECTION
1. Check for short to ground in signal circuit
1. Measure resistance between terminal 2 of the A/C pressure sensor harness connector and chassis ground.
Specification : Infinite
2. Is resistance within the specification?
YES - Go to next step as below.
NO - Check for short to ground in signal circuit. Repair as necessary and go to "Verification of Vehicle Repair" procedure
2. Check for open in signal circuit
1. Measure resistance between terminals 2 of the A/C pressure sensor harness connector and 35 of the ECM harness connector.
Specification : Approx. 0 ohm
2. Is resistance within the specification?
YES - Go to next step as below.
NO - Check for open in signal circuit. Repair as necessary and go to "Verification of Vehicle Repair" procedure
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, damage.
3. Has a problem been found?
YES - Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below
COMPONENT INSPECTION
1. Reconnect A/C pressure sensor and ECM connectors.
2. Set up an oscilloscope as follows :
Channel A (+): Terminal 2 of the A/C pressure sensor (back probe), (-): Ground
3. Start the engine to normal operating temperature and Measure voltage between terminal 2 of the A/C pressure sensor harness connector (back probe) and chassis ground.
Specification : Approx. below 1.3 - 1.5 V at A/C OFF with idle
Approx. above 1.5 V at A/C ON with idle
NOTE: Signal waveform of the A/C pressure sensor
A : Approx. below 1.3 - 1.5 V at A/C OFF with idle
B : Approx. above 1.5 V at A/C ON with idle
4. Is voltage within the specification?
YES - Check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below.
5. Return vehicle to original condition.
6. Ignition "ON" & Engine "OFF".
7. Is the A/C compressor clutch engaged?
YES - Disconnect A/C clutch relay and check the A/C compressor clutch status.
- If engaged, repair open/short circuit in the A/C compressor clutch harness or replace faulty compressor clutch assembly. And go to "Verification of Vehicle Repair" procedure
- If disengaged, repair open/short circuit in the A/C clutch relay harness or replace faulty clutch relay. And go to "Verification of Vehicle Repair" procedure
NO - Go to next step as below
8. Start the engine to normal operating temperature.
9. Turn the A/C ON and OFF.
10. Does the A/C compressor clutch cycle ON and OFF with the selector switch?
YES - Check A/C pressure sensor for contamination, deterioration, or damage. Substitute with a known-good A/C pressure sensor and check for proper operation. If the problem is corrected, replace A/C pressure sensor and then go to "Verification of Vehicle Repair" procedure
NO - Monitor the " A/C SWITCH & A/C COMPRESSOR" parameters on the Scantool data list. Refer to "Signal Waveform & Data" in the "General Information" procedure.
- Turn the A/C ON and OFF.
- Check the scantool indicate when the A/C is ON and OFF correctly.
If OK, check the A/C pressure. Refer to A/C group in Workshop Manual. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
If NG, repair the signal from the A/C selector switch and compressor switch. Go to "Verification of Vehicle Repair" procedure
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Press F4 (DTAL) and confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
3. Read "DTC Status" parameter.
4. Is parameter displayed "History (Not Present) fault"?
YES - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.