P0108
P0108-MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT HIGHP0108 - Manifold Absolute Pressure Sensor Circuit High:
WHEN MONITORED
Engine speed between 600 to 3500 RPM. Battery voltage greater than 10.37 volts.
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. (5.7L ETC light will flash).
POSSIBLE CAUSES
- (K1) MAP signal circuit shorted to battery voltage
- (K1) MAP signal circuit open
- (K1) MAP signal circuit shorted to the (F856) 5-volt supply circuit (K900) sensor ground circuit open
- MAP sensor
- PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. MAP SENSOR VOLTAGE ABOVE 4.92 VOLTS
Start the engine.
With a scan tool, read the MAP Sensor voltage.
Q: Is the voltage above 4.92 volts?
YES: Go To 2
NO: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
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.
Q: Is the voltage below 1.0 volt with the jumper wire installed?
YES: Replace the MAP Sensor. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 3
NOTE: Remove the jumper wire before continuing.
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.
Q: Is the voltage above 0 volts?
YES: Repair the short to battery voltage in the (K1) MAP Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 4
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.
Q: Is the resistance below 5.0 ohms?
YES: Go To 5
NO: Repair the open in the (K1) MAP Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
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.
Q: Is the resistance below 100 ohms?
YES: Repair the short between the (F856) 5-volt Supply circuit and the (K1) MAP Signal circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 6
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.
Q: Is the resistance below 5.0 ohms?
YES: Go To 7
NO: Repair the open in the (K900) Sensor ground circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
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.
Q: Were there any problems found?
YES: Repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Replace and program the Powertrain Control Module per Service Information. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test