P0108-MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT HIGH
For a complete wiring diagram Refer to Section 8W.
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When Monitored:
Engine speed between 600 to 3500 RPM. Battery voltage greater than 10.37 volts.
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Set Condition:
The MAP sensor signal voltage is greater than 4.92 volts for 3.0 seconds. One trip fault. Three good trips to turn off the MIL. MIL will illuminate and the ETC light will flash if equipped.
Possible Causes
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(K1) MAP SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
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(K1) MAP SIGNAL CIRCUIT OPEN
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(K1) MAP SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
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(K900) SENSOR GROUND CIRCUIT OPEN
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MAP SENSOR
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PCM
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Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1.
MAP SENSOR VOLTAGE ABOVE 4.92 VOLTS
Start the engine.
With a scan tool, read the MAP Sensor voltage.
Is the voltage above 4.92 volts?
Yes
No
2.
MAP SENSOR
Turn the ignition off.
Disconnect the MAP Sensor harness connector.
Connect a jumper wire between the (K1) MAP Signal circuit and the (K900) Sensor ground circuit in the Sensor harness connector.
Ignition on, engine not running.
With a scan tool, monitor the MAP Sensor voltage.
Is the voltage below 1.0 volt with the jumper wire installed?
Yes
No
3.
(K1) MAP SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the C1 and C2 PCM harness connectors.
Ignition on, engine not running.
Measure the voltage on the (K1) MAP Signal circuit in the MAP Sensor harness connector.
Is the voltage above 5.2 volts?
Yes
No
4.
(K1) MAP SIGNAL CIRCUIT OPEN
Turn the ignition off.
CAUTION:
Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller
Special Tool #8815 to perform diagnosis.
Measure the resistance of the (K1) MAP Signal circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
No
5.
(K1) MAP SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
Measure the resistance between the (K1) MAP Signal circuit and the (F856) 5-volt Supply circuit in the MAP Sensor harness connector.
Is the resistance below 100 ohms?
Yes
No
6.
(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the MAP Sensor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
No
7.
PCM
NOTE:
Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes
No