Inspection Procedure 34
A/C Pressure Sensor SystemA/C Pressure Sensor Circuit Part 1:
A/C Pressure Sensor Circuit Part 2:
CIRCUIT OPERATION
- A 5-volt voltage is supplied to the A/C pressure sensor power terminal (terminal No. 3) from the PCM (terminal No. 97). The ground terminal (terminal No. 1) is grounded with the PCM (terminal No. 96).
- A voltage that is proportional to the A/C refrigerant pressure is sent from the A/C pressure sensor output terminal (terminal No. 2) to the PCM (terminal No. 118).
TECHNICAL DESCRIPTION
- The A/C pressure sensor detects the A/C refrigerant pressure and inputs it into the PCM.
- The PCM uses this signal for fuel injection mode control.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are: )
- A/C pressure sensor failed.
- Open or shorted A/C pressure sensor circuit, or connector damage.
- PCM failed.
DIAGNOSIS
STEP 1. Measure the sensor output voltage at A/C pressure sensor connector A-02 by backprobing.
1. Do not disconnect the connector A-02.
2. Start the engine and run at idle.
3. Turn the A/C switch to the "ON" position.
4. Measure the voltage between terminal No. 2 and ground by backprobing.
- When A/C refrigerant pressure is 1 kPa, voltage should be between 1.8 and 2.0 volts.
- When A/C refrigerant pressure is 2 kPa, voltage should be between 3.23 and 3.57 volts.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage within the specified range?
YES: Go to Step 12.
NO: Go to Step 2.
STEP 2. Measure the sensor supply voltage at A/C pressure sensor connector A-02 by backprobing.
1. Do not disconnect the connector A-02.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No. 3 and ground by backprobing.
- Voltage should be between 4.9 and 5.1 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.9 and 5.1 volts?
YES: Go to Step 7.
NO: Go to Step 3.
STEP 3. Measure the sensor supply voltage at PCM connector C-112 by backprobing.
1. Do not disconnect the connector C-112.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No. 97 and ground by backprobing.
- Voltage should be between 4.9 and 5.1 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.9 and 5.1 volts?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check harness connector C-112 at PCM and harness connector A-02 at A/C pressure sensor for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 5. Check for short circuit to ground between A/C pressure sensor connector A-02 (terminal No. 3) and PCM connector C-112 (terminal No. 97).
NOTE: Check harness after checking intermediate connector A-14. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
Q: Is the harness wire in good condition?
YES: Replace the PCM. Then confirm that the malfunction symptom is eliminated.
NO: Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 6. Check harness connector C-112 at PCM and harness connector A-02 at A/C pressure sensor for damage.
Q: Is the harness connector in good condition?
YES: Check the connector A-14 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connector is in good condition, repair harness wire between A/C pressure sensor connector A-02 (terminal No. 3) and PCM connector C-112 (terminal No. 97) because of open circuit and harness damage. Then confirm that the malfunction symptom is eliminated.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 7. Measure the ground voltage at A/C pressure sensor connector A-02 by backprobing.
1. Do not disconnect the connector A-02.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No. 1 and ground by backprobing.
- Voltage should be 0.5 volt or less.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage 0.5 volt or less?
YES: Go to Step 10.
NO: Go to Step 8.
STEP 8. Check harness connector C-112 at PCM and harness connector A-02 at A/C pressure sensor for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 9.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 9. Check for open circuit and harness damage between A/C pressure sensor connector A-02 (terminal No. 1) and PCM connector C-112 (terminal No. 96).
NOTE: Check harness after checking intermediate connectors C-105 and C-116. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
Q: Is the harness wire in good condition?
YES: Replace the PCM. Then confirm that the malfunction symptom is eliminated.
NO: Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 10. Check harness connector C-112 at PCM and harness connector A-02 at A/C pressure sensor for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 11.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 11. Check for short circuit to ground and harness damage between A/C pressure sensor connector A-02 (terminal No. 2) and PCM connector C-112 (terminal No. 118).
NOTE: Check harness after checking intermediate connectors C-104 and C-116. If intermediate connectors are damaged, repair or replace them. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
Q: Is the harness wire in good condition?
YES: Replace the A/C pressure sensor. Then confirm that the malfunction symptom is eliminated.
NO: Repair it. Then confirm that the malfunction symptom is eliminated.
STEP 12. Measure the sensor output voltage at PCM connector C-112 by backprobing.
1. Do not disconnect the connector C-112.
2. Start the engine and run at idle.
3. Turn the A/C switch to the "ON" position.
4. Measure the voltage between terminal No. 118 and ground by backprobing.
- When A/C refrigerant pressure is 1 kPa, voltage should be between 1.8 and 2.0 volts.
- When A/C refrigerant pressure is 2 kPa, voltage should be between 3.23 and 3.57 volts.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage within the specified range?
YES: Go to Step 14.
NO: Go to Step 13.
STEP 13. Check harness connector C-112 at PCM and harness connector A-02 at A/C pressure sensor for damage.
Q: Is the harness connector in good condition?
YES: Check the connectors C-104 and C-116 at intermediate connectors for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connectors are in good condition, repair harness wire between A/C pressure sensor connector A-02 (terminal No. 2) and PCM connector C-112 (terminal No. 118) because of open circuit and harness damage. Then confirm that the malfunction symptom is eliminated.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 14. Check harness connector C-112 at PCM and harness connector A-02 at A/C pressure sensor for damage.
Q: Is the harness connector in good condition?
YES: Replace the PCM. Then confirm that malfunction symptom is eliminated.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.