P0108
Barometric Pressure Sensor Circuit:
Connectors:
CIRCUIT OPERATION
- A 5-volt voltage is supplied to the barometric pressure sensor power terminal (terminal 1) from the ECM (terminal 81)
- A voltage that is proportional to the atmospheric pressure is sent to the ECM (terminal 85)
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 signal has continued to be approximately 113 kPa (16 psi) or higher (approximately 4,000 it 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 Tools
- 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.
- When altitude is 600 m (1,969 feet), 95 kPa.
- When altitude is 1,200 m (3,937 feet), 88 kPa.
- When altitude is 1,800 m (5,906 feet), 81 kPa.
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 How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check the sensor output voltage at barometric pressure sensor connector B-105 by backprobing.
1. Do not disconnect the connector B-105.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 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.
STEP 3. Check connector B-105 at the barometric pressure sensor and connector C-115 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.
- When altitude is 600 m (1,969 feet), 95 kPa.
- When altitude is 1,200 m (3,937 feet), 88 kPa.
- When altitude is 1,800 m (5,906 feet), 81 kPa.
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 How to Use Troubleshooting/Inspection Service Points.
NO: Replace the ECM or PCM. Then go to Step 12.
STEP 5. Check the sensor supply voltage at barometric pressure sensor connector B-105 by backprobing.
1. Do not disconnect the connector B-105.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 1 and ground by backprobing.
- Voltage should be between 4.8 and 5.2 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 7.
NO: Go to Step 6.
STEP 6. Check connector C-115 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. Check the ground voltage at barometric pressure sensor connector B-105 by backprobing.
1. Do not disconnect the connector B-105.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 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 voltage normal?
YES: Go to Step 10.
NO: Go to Step 8.
STEP 8. Check connector B-105 at the barometric pressure sensor and connector C-119 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-105 terminal 5 and ECM connector C-119 terminal 40
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-105 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.
STEP 11. Check connector C-119 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 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, Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is the DTC P0108 output?
YES: Retry the troubleshooting.
NO: The inspection is complete.