P0108

P0108-MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT HIGH

For a complete wiring diagram, refer to the Wiring Information.

Theory of operation

The Manifold Absolute Pressure (MAP) sensor is a transducer that varies resistance according to changes in altitude and atmospheric conditions. The MAP reading gives the Powertrain Control Module (PCM) an indication of the current air pressure within the intake manifold. The PCM uses this information to calculate fuel delivery. The MAP sensor has a 5 Volt reference circuit, a low reference circuit and a signal circuit. The PCM supplies 5 Volts to the MAP sensor on a 5 Volt reference circuit and provides a ground on a low reference circuit. The MAP sensor provides a voltage signal to the PCM on a signal circuit relative to the pressure changes.

- 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 the maximum acceptable value. One trip fault. Three good trips to turn off the MIL. MIL will illuminate and the ETC light will flash if equipped.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Start the engine and allow it to reach normal operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.

NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.

2. With the scan tool, read the active DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. MAP SENSOR
1. Turn the ignition off.
2. Disconnect the MAP Sensor harness connector.
3. Ignition on, engine not running.
4. With the scan tool, monitor the MAP Sensor voltage.
5. Connect a jumper wire between the MAP Signal circuit and the Sensor ground circuit in the Sensor harness connector.

NOTE: The sensor voltage should be approximately 0.0 Volts (plus or minus.1 of a Volt) with the jumper wire in place.

Does the scan tool display the voltage as described above?

Yes

- Verify that there is good pin to terminal contact in the MAP Sensor and Powertrain Control Module connectors. If OK, replace the MAP Sensor. Removal.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 3
NOTE: Remove the jumper wire before continuing.


3. MAP SIGNAL CIRCUIT SHORTED TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connectors.
3. Ignition on, engine not running.
4. Measure the voltage on the MAP Signal circuit in the MAP Sensor harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the MAP Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. MAP SIGNAL CIRCUIT OPEN
1. Turn the ignition off.
2. Measure the resistance of the MAP Signal circuit from the MAP Sensor harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 5

No

- Repair the open or excessive resistance in the MAP Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. MAP SIGNAL CIRCUIT SHORTED TO THE 5 VOLT SUPPLY CIRCUIT
1. Measure the resistance between the MAP Signal circuit and the 5 Volt Supply circuit in the MAP Sensor harness connector.

Is the resistance below 100 Ohms?

Yes

- Repair the short between the 5 Volt Supply circuit and the MAP Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 6

6. SENSOR GROUND CIRCUIT OPEN
1. Measure the resistance of the Sensor ground circuit from the MAP Sensor harness connector to the PCM C2 harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 7

No

- Repair the open or excessive resistance in the Sensor ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

7. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the MAP Sensor and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

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. PCM/ECM Reprogramming.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.