P0108
DTC P0108: Manifold Absolute Pressure Circuit High InputManifold Absolute Pressure Sensor Circuit:
CIRCUIT OPERATION
- A 5-volt voltage is supplied to the manifold absolute pressure sensor power terminal (terminal No.3) from ECM (terminal No.42). The ground terminal (terminal No.2) is grounded with the ECM (terminal No.49).
- A voltage that is proportional to the intake manifold pressure is sent to the ECM (terminal No.92) from the manifold absolute pressure sensor output terminal (terminal No.1).
TECHNICAL DESCRIPTION
- The manifold absolute pressure sensor outputs a voltage which corresponds to the intake manifold pressure.
- The ECM checks whether this voltage is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
Manifold absolute pressure sensor output voltage is out of specified range.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Engine coolant temperature sensor
- Throttle position sensor
- Volume airflow sensor
- Intake air temperature sensor
- Barometric pressure sensor
DTC SET CONDITION
Logic Flow Chart:
Logic Flow Chart
Check Conditions
- 8 minutes or more have passed since the engine starting sequence was completed, when the engine coolant temperature at engine start is 0 degree C (32 degrees F) or lower.
- Volumetric efficiency is lower than 75 percent.
Judgment Criterion
- Manifold absolute pressure is 121 kPa (35.7 in.Hg) or higher for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Manifold absolute pressure sensor failed.
- Open manifold absolute pressure sensor circuit, or connector damage.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
STEP 1. Using scan tool MB991958, check data list item 95: Manifold Absolute Pressure Sensor.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the data reading mode for item 95, Manifold Absolute 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 (28.1 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. Start the engine.
- When the engine is idling, 31 - 45 kPa (9.1 - 13.2 in.Hg).
- When the engine is suddenly revved, manifold absolute pressure increases.
5. 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.
NO: Go to Step 2.
STEP 2. Measure the sensor output voltage at manifold absolute pressure sensor connector B-125 by backprobing.
1. Do not disconnect the connector B-125.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.1 and ground by backprobing.
- When altitude is 0 m (0 foot), voltage should be 3.8 and 4.2 volts.
- When altitude is 600 m (1,969 feet), voltage should be 3.5 and 3.9 volts.
- When altitude is 1,200 m (3,937 feet), voltage should be 3.3 and 3.7 volts.
- When altitude is 1,800 m (5,906 feet), voltage should be 3.0 and 3.4 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage normal?
YES: Go to Step 3.
NO: Go to Step 5.
STEP 3. Check harness connector B-125 at the manifold absolute pressure sensor and connector C-117 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 4.
NO: Repair or replace it. Then go to Step 12.
STEP 4. Using scan tool MB991958, check data list item 95: Manifold Absolute Pressure Sensor.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991958 to the data reading mode for item 95, Manifold Absolute 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 (28.1 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. Start the engine.
- When the engine is idling, 31 - 45 kPa (9.1 - 13.2 in.Hg).
- When the engine is suddenly revved, manifold absolute pressure increases.
5. 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.
NO: Replace the ECM. Then go to Step 12.
STEP 5. Measure the sensor supply voltage at manifold absolute pressure sensor connector B-125 by backprobing.
1. Do not disconnect the connector B-125.
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 4.8 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.
STEP 6. Check harness connector C-119 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Replace the ECM. Then go to Step 12.
NO: Repair or replace it. Then go to Step 12.
STEP 7. Measure the ground voltage at manifold absolute pressure sensor connector B-125 by backprobing.
1. Do not disconnect the connector B-125.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.2 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 B-125 at the manifold absolute pressure sensor and connector C-119 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 9.
NO: Repair or replace it. Then go to Step 12.
STEP 9. Check for open circuit between manifold absolute pressure sensor connector B-125 (terminal No.2) and ECM connector C-119 (terminal No.49).
Q: Is the harness wire in good condition?
YES: Replace the ECM. Then go to Step 12.
NO: Repair it. Then go to Step 12.
STEP 10. Check harness connector B-125 at manifold absolute pressure sensor for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 11.
NO: Repair or replace it. Then go to Step 12.
STEP 11. Check harness connector C-119 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Replace the manifold absolute pressure sensor. Then go to Step 12.
NO: Repair or replace it. 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 Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0108 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.