P0108

DTC P0108: Manifold Absolute Pressure Circuit High Input

Manifold Absolute Pressure Sensor Circuit Part 1:

Manifold Absolute Pressure Sensor Circuit Part 2:

CIRCUIT OPERATION
- A 5-volt voltage is supplied to the manifold absolute pressure sensor power terminal (terminal No. 3) from ECM (terminal No. 42) or PCM (terminal No. 46). The ground terminal (terminal No. 2) is grounded with ECM (terminal No. 49) or PCM (terminal No. 57).
- A voltage that is proportional to the intake manifold pressure is sent to the ECM (terminal No. 92) or PCM (terminal No. 91) 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 or PCM 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 )
- Not applicable

Sensor (The sensor below is determined to be normal)
- Engine coolant temperature sensor
- Throttle position sensor

DTC SET CONDITIONS

Logic Flow Chart:

Logic Flow Chart

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

Judgement Criteria
- Manifold absolute pressure is 117 kPa (34.6 in.Hg) or higher for 2 seconds.

OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor. 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.
- PCM failed.

DIAGNOSIS

Required Special Tools:
- MB991958: Scan Tool (MUT-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, 18 - 38 kPa (5.3 - 11.2 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. Refer to How to Use Troubleshooting/ Inspection Service Points.

NO: Go to Step 2.

STEP 2. Measure the sensor output voltage at manifold absolute pressure sensor connector B-04 by backprobing.

1. Do not disconnect the connector B-04.
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 3.7 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.