P0108

DTC P0108: Manifold Absolute Pressure Circuit High Input














CIRCUIT OPERATION

- A 5-volt voltage is supplied to the manifold absolute pressure sensor power terminal (terminal No. 3) from ECM (terminal No. 44). The ground terminal (terminal No. 2) is grounded with ECM (terminal No. 46).
- A voltage that is proportional to the intake manifold pressure is sent to the ECM (terminal No. 45) 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
- Mass airflow sensor
- Intake air temperature sensor
- Barometric pressure sensor

DTC SET CONDITIONS

Logic Flow Chart





Check Condition

- 8 minutes or more have passed since the engine starting sequence was completed, when the engine coolant temperature at engine start is 0°C (32°F) or lower.
Judgement Criterion

- Manifold absolute pressure sensor output voltage has continued to be 4.6 volts [corresponding to a manifold absolute pressure of 314 kPa (92.7 in.Hg)] or higher for 2 seconds.

FAIL-SAFE AND BACKUP FUNCTION

- None

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 Monitors, Trips, Drive Cycles and Readiness Codes .

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
- MB991910: Main Harness A

STEP 1. Using scan tool MB991958, check data list item 8: 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 8, 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 - 13.3 in.Hg).
- When the engine is suddenly revved, manifold absolute pressure varies.
(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. How to Cope With Intermittent Malfunctions.

NO Go to Step 2.

STEP 2. Measure the ground voltage at manifold absolute pressure sensor connector B-18 by backprobing.

(1)Do not disconnect the connector B-18.

(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 6.

NO Go to Step 3.

STEP 3. Check harness connector B-18 at the manifold absolute pressure sensor and harness connector B-09 at ECM for damage.

Q. Is the harness connector in good condition?

YES Go to Step 4.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 7.
STEP 4. Check for open circuit between manifold absolute pressure sensor connector B-18 (terminal No. 2) and ECM connector B-09 (terminal No. 46).

Q. Is the harness wire in good condition?

YES Go to Step 5.
NO Repair it. Then go to Step 7.
STEP 5. Using scan tool MB991958, check data list item 8: Manifold Absolute Pressure Sensor.

(1)Turn the ignition switch to the "ON" position.

(2)Set scan tool MB991958 to the data reading mode for item 8, 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).

(3)Start the engine.

- When the engine is idling, 31 - 45 kPa (9.1 - 13.3 in.Hg).
- When the engine is suddenly revved, manifold absolute pressure varies.

(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. How to Cope With Intermittent Malfunctions.
NO Replace the ECM (Refer to, Removal and Installation Removal and Replacement).
Then go to Step 7.
STEP 6. Check harness connector B-18 at the manifold absolute pressure sensor and harness connector B-09 at ECM for damage.

Q. Is the harness connector in good condition?

YES Replace the manifold absolute pressure sensor. Then go to Step 7.
NO Repair or replace it. Harness Connector Inspection.
Then go to Step 7.
STEP 7. 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 Monitors, Trips, Drive Cycles and Readiness Codes.

(2)Check the diagnostic trouble code (DTC).

Q. Is DTC P0108 set?

YES Retry the troubleshooting.
NO The inspection is complete.