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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 set in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Mass airflow sensor
  • Engine coolant temperature sensor
  • Intake air temperature sensor
  • Barometric pressure sensor
  • Throttle position sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Condition
  • More than 8 minutes have passed since the engine starting sequence was completed, when the engine coolant temperature at engine start is less than 0°C (32°F).
Judgment Criterion
  • Manifold absolute pressure sensor output voltage is more than 4.6 volts [corresponding to a manifold absolute pressure of 117 kPa (34.6 in.Hg)] for 2 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Control as if the intake manifold vacuum pressure is 101 kPa (29.8 in.Hg).
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23 .
 
 
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 Tool:
  • 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.
cautionTo 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.
  • Warm up the engine. When the engine is idling, 16 - 36 kPa (4.7 - 10.6 in.Hg).
  • When the engine is suddenly revved, manifold absolute pressure varies.
(5) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Go to Step 2.
 
STEP 2. Measure the ground voltage at manifold absolute 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.
  • Voltage should be 0.5 volt or less.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the measured voltage 0.5 volt or less?
Go to Step 6.
Go to Step 3.
 
STEP 3. Check harness connector B-14 at manifold absolute pressure sensor and harness connector B-26 at ECM for damage.
Are the harness connectors in good condition?
Go to Step 4.
Repair or replace them. Refer to GROUP 00E, Harness Connector Inspection . Then go to Step 7.
 
STEP 4. Check for open circuit between manifold absolute pressure sensor connector B-14 (terminal No. 2) and ECM connector B-26 (terminal No. 46).
Is the harness wire in good condition?
Go to Step 5.
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.
  • Warm up the engine. When the engine is idling, 16 - 36 kPa (4.7 - 10.6 in.Hg).
  • When the engine is suddenly revved, manifold absolute pressure varies.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the sensor operating properly?
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
Replace the ECM (Refer to, Removal and Installation ). Then go to Step 7.
 
STEP 6. Check harness connector B-14 at manifold absolute pressure sensor and harness connector B-26 at ECM for damage.
Are the harness connectors in good condition?
Replace the manifold absolute pressure sensor. Then go to Step 7.
Repair or replace them. Refer to GROUP 00E, 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 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0108 set?
Retry the troubleshooting.
The inspection is complete.