P0108
P0108-INLET AIR Pressure Sensor Voltage Too highP0108 - Inlet Air Pressure Sensor Voltage Too High:
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.
POSSIBLE CAUSES
- other DTC's present
- Inlet air pressure sensor
- Inlet air pressure sensor (K616) signal circuit shorted to voltage
- Inlet air sensor (K668) 5-volt supply circuit shorted to voltage
- (K616) Signal circuit shorted to (K668) 5-volt supply
- (K690) Return circuit open
- ECM
- Intermittent condition
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. OTHER DTC'S PRESENT
Ignition on, engine not running.
With the scan tool, read DTCs.
Q: Do you have multiple DTC's?
YES: Repair other DTC's first. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 2
2. CHECKING (K668) 5-VOLT SUPPLY CIRCUIT AND THE (K690) RETURN CIRCUIT
Disconnect the Inlet Air Pressure sensor harness connector.
Measure the voltage between the (K668) 5-volt supply circuit and (K690) return circuit of the Inlet Air Pressure sensor harness connector.
Q: Is the voltage between 4.5 and 5.5 volts?
YES: Go To 3
NO: Go To 4
3. INLET AIR PRESSURE SENSOR
While monitoring scan tool, use a jumper wire to connect the (K690) Return circuit to the (K616) signal circuit at the Inlet Air Pressure sensor harness connector.
Q: Does the scan tool show a P0107 Inlet Air Pressure Sensor Low DTC?
YES: Replace the Inlet Air Temperature/Pressure sensor. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 4
4. INLET AIR SENSOR (K616) SIGNAL CIRCUIT SHORTED TO VOLTAGE
Disconnect the ECM harness connectors.
NOTE: Check connectors - Clean/repair as necessary.
Measure the voltage between the (K616) signal circuit of the Inlet Air Pressure sensor connector and battery negative.
Q: Is the voltage less than 1 volt?
YES: Go To 5
NO: Repair or replace short to voltage. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
5. (K668) 5-VOLT SUPPLY CIRCUIT SHORTED TO VOLTAGE
Measure the voltage between the (K668) 5-volt supply circuit of the sensor connector and battery negative.
Q: Is the voltage less than 1 volt?
YES: Go To 6
NO: Repair the short to voltage or replace the harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
6. SIGNAL CIRCUIT SORTED TO (K668) 5-VOLT SUPPLY
Turn the ignition off.
Measure the resistance between the (K616) signal circuit and the (K668) 5-volt supply circuit of the Inlet Air Pressure sensor harness connector.
Q: Is the resistance less than 10 Ohms?
YES: Go To 7
NO: Repair or replace the shorted wiring harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
7. (K690) RETURN CIRCUIT OPEN
Disconnect the ECM harness connector.
Check connectors - Clean/repair as necessary.
Measure the resistance between the (K690) return circuit in the Inlet Air Pressure sensor harness connector with the (K690) return circuit in the ECM harness connector.
Q: Is the resistance less than 10 Ohms?
YES: Go To 8
NO: Repair or replace the Engine harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
8. ECM
Install the ECM harness connector.
Turn the ignition on.
While monitoring scan tool, use a jumper wire to connect the (K916) Return circuit with the (K616) signal circuit at the Inlet Air Pressure sensor harness connector.
Q: Did DTC P0107 set?
YES: Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Replace the ECM. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1