P0108

P0108-MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT HIGH





For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The Electronic Control Module (ECM) provides a 5-volt supply to the intake manifold pressure sensor on the sensor supply circuit. The ECM also provides a ground on the sensor return circuit. The intake manifold pressure sensor provides a signal to the ECM on the intake manifold pressure sensor signal circuit. This sensor signal voltage changes based on the pressure in the intake manifold. The ECM will detect a low signal voltage at operating conditions such as during an idle or a deceleration. The ECM will detect a high signal voltage during high engine load operating conditions. The ECM illuminates the MIL light immediately when the diagnostic runs and fails and a default value is used for the intake manifold pressure reading. The ETC lamp will also be illuminated. The ECM will turn off the MIL light after the diagnostic runs and passes in 4 consecutive drive cycles. This fault may cause a derate in power output

- When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.

- Set Condition:
The circuit voltage to the ECM is above a calibrated threshold for a certain period of time.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. OTHER DTC'S
Turn the ignition on.
With the scan tool, read the Engine DTC's.
Is there a 5-volt Supply DTC set?

Yes


- Repair all 5-volt Supply DTC's first.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To 2



2. P108 SET
With the scan tool, read the Engine DTC's.


Yes


- Go To 3


No


- Refer to the INTERMITTENT CONDITION - DIESEL Symptom. Intermittent Condition



3. HIGH VOLTAGE




Turn the ignition off.
Disconnect the MAP sensor harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Turn the ignition on.
Measure the voltage between the (F855) 5-volt supply circuit and (K916) sensor return circuit of the MAP sensor harness connector.
Is the voltage between 4.5 and 5.5 volts?

Yes


- Go To 4


No


- Go To 5



4. MAP SENSOR




While monitoring scan tool, use a jumper wire to connect the (K916) return circuit with the (K37) signal circuit at the sensor connector.
Did the P0107-MAP SENSOR VOLTAGE TOO LOW, DTC set?

Yes


- Go To 5


No


- Replace the MAP sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



5. (K37) SIGNAL CIRCUIT SHORTED TO BATTERY




Turn the ignition off.
Disconnect the ECM harness connectors.

NOTE: Check connectors - Clean/repair as necessary.

Measure the voltage between the (K37) signal circuit at the MAP sensor harness connector and Battery Negative.
Is the voltage greater than 1 volt?

Yes


- Repair (K37) signal circuit shorted to battery.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To 6



6. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO BATTERY




Measure the voltage between the (F855) 5-volt supply circuit at the MAP sensor harness connector and Battery negative.
Is the voltage greater than 1 volt?

Yes


- Repair (F855) 5-volt supply circuit shorted to Battery or replace harness.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test


No


- Go To 7



7. (K37) SIGNAL CIRCUIT SHORT TO 5-VOLT SUPPLY




Turn the ignition off.
Disconnect the ECM harness connectors.
Measure the resistance between the (K37) signal circuit of the sensor harness connector and the (F855) 5-volt supply circuit of the sensor harness connector.
Is the resistance less than 10 Ohms?

No


- Go To 8


Yes


- Repair or replace the engine harness.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



8. (F855) SENSOR RETURN CIRCUIT OPEN




Measure the resistance between the (K916) sensor return circuit in the MAP sensor harness connector with the (K916) sensor return circuit in the ECM harness connector.
Is the resistance less than 10 Ohms?

Yes


- Go To 9


No


- Repair or replace the engine harness.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test



9. INTERMITTENT CONDITION




Reconnect the ECM harness connector.
Turn the ignition on.
While monitoring scan tool, connect a jumper wire between the (K37) signal circuit of the sensor harness connector and the (K916) return circuit of the sensor harness connector.
Does the scan tool show P0107-MAP Sensor Voltage Too Low DTC?

Yes


- Refer to the INTERMITTENT CONDITION - DIESEL Symptom (Diagnostic Procedure). Intermittent Condition


No


- Replace and program the ECM.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test