P0108
Barometric Pressure Sensor Circuit:
Connectors:
CIRCUIT OPERATION
- A 5-volt voltage is supplied to the barometric pressure sensor power terminal (terminal No.1) from the ECM (terminal No.42)
- A voltage that is proportional to the atmospheric pressure is sent to the ECM (terminal No.51)
TECHNICAL DESCRIPTION
- The barometric pressure sensor outputs a voltage which corresponds to the barometric pressure.
- The ECM
DTC SET CONDITIONS
Check Conditions
- 2 seconds or more have passed since the starting sequence was completed.
- Battery positive voltage is higher than 8 volts.
Judgement Criteria
- Barometric pressure sensor output has continued to be 113 kPa (16 psi) or higher approximately 4,000 ft below sea level for 10 seconds.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Barometric pressure sensor failed.
- Open or shorted barometric pressure sensor circuit, or loose connector.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tool:
- MB991502: Scan Tool (MUT-II)
STEP 1. Using scan tool MB991502, check data list item 25: Barometric Pressure Sensor.
CAUTION
To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991502 to the data reading mode for item 25, Barometric Pressure Sensor.
- When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg).
- When altitude is 600 m (1,969 feet), 95 kPa (28.0 in.Hg).
- When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg).
- When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg).
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent. Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Measure the sensor output voltage at barometric pressure sensor connector B-14 by backprobing.
1. Do not disconnect the connector B-14.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.2 and ground by backprobing.
- When altitude is 0 m (0 foot), voltage should be 3.7 and 4.3 volts.
- When altitude is 600 m (1,969 feet), voltage should be 3.4 and 4.0 volts.
- When altitude is 1,200 m (3,937 feet), voltage should be 3.2 and 3.8 volts.
- When altitude is 1,800 m (5,906 feet), voltage should be 2.9 and 3.5 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 3.
NO: Go to Step 5.
Connectors:
STEP 3. Check connector B-14 at the barometric pressure sensor and connector C-118 at ECM
Q: Is the connector in good condition?
YES: Go to Step 4.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 4. Using scan tool MB991502, check data list item 25: Barometric Pressure Sensor.
CAUTION
To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991502 to the data reading mode for item 25, Barometric Pressure Sensor.
- When altitude is 0 m (0 foot), 101 kPa (29.8 in.Hg).
- When altitude is 600 m (1,969 feet), 95 kPa (28.0 in.Hg).
- When altitude is 1,200 m (3,937 feet), 88 kPa (26.0 in.Hg).
- When altitude is 1,800 m (5,906 feet), 81 kPa (23.9 in.Hg).
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: It can be assumed that this malfunction is intermittent. Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Replace the ECM or PCM. Then go to Step 12.
STEP 5. Measure the sensor supply voltage at barometric pressure sensor connector B-14 by backprobing.
1. Do not disconnect the connector B-14.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.1 and ground by backprobing.
- Voltage should be between4.8 and 5.2 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.8 and 5.2 volts?
YES: Go to Step 7.
NO: Go to Step 6.
Connectors:
STEP 6. Check connector C-118 at ECM
Q: Is the connector in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 7. Measure the ground voltage at barometric pressure sensor connector B-14 by backprobing.
1. Do not disconnect the connector B-14.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.5 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.
Connectors:
STEP 8. Check connector B-14 at the barometric pressure sensor and connector C-111 at ECM
Q: Is the connector in good condition?
YES: Go to Step 9.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 9. Check for open circuit between barometric pressure sensor connector B-14 (terminal No.5) and ECM connector C-111 (terminal No.34)
Q: Is the harness wire in good condition?
YES: Replace the ECM or PCM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 10. Check connector B-14 at barometric pressure sensor for damage.
Q: Is the connector in good condition?
YES: Go to Step 11.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
Connectors:
STEP 11. Check connector C-111 at ECM
Q: Is the connector in good condition?
YES: Replace the volume air flow sensor. Then go to Step 12.
NO: Repair or replace it. Refer to GROUP 8W1 Harness Connector Inspection. Then go to Step 12.
STEP 12. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Trouble Code Diagnosis - OBD-II Drive Cycle - Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0108 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.