For a complete wiring diagram Refer to Section 8WWhen Monitored:With the ignition on.Set Condition:The (K68) Inlet Air Pressure Sensor Signal circuit voltage is below 0.35 volt for 0.5 second.Possible CausesINTERMITTENT DTC(K668) INLET AIR PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND(K68) INLET AIR PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND(K668) INLET AIR PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO (K901) INLET AIR PRESSURE SENSOR GROUND(K68) INLET AIR PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO (K901) INLET AIR PRESSURE SENSOR GROUND(K668) INLET AIR PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE(K68) INLET AIR PRESSURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCEINLET AIR PRESSURE SENSORENGINE CONTROL MODULE (ECM)Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)1. DTC IS ACTIVEIf any Sensor Reference or Sensor Supply voltage DTCs are present, perform the applicable diagnostic procedure before continuing with this test.Ignition on, engine not running.With the scan tool, Clear DTCs in the Engine Control Module (ECM).Monitor the scan tool for at least two minutes.Cycle the ignition key off and on several times, leaving the ignition on for at least 10 seconds at a time.Start the engine.Allow the engine to reach normal operating temperature.With the scan tool, select View DTCs.Is the status Active for this DTC?YesGo To 2 NoRefer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.(Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)2. (K668) INLET AIR PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT VOLTAGE

Turn the ignition off.Disconnect the Inlet Air Pressure Sensor harness connector.Turn the ignition on.Measure the voltage of the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit in the Inlet Air Pressure Sensor harness connector.Is the voltage above 4.5 volts?YesGo to 6NoGo to 33. (K668) INLET AIR PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Turn the ignition on.Disconnect the Engine Control Module (ECM) harness connector.Measure the resistance between ground and the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit in the Inlet Air Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 4NoRepair the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)4. (K668) INLET AIR PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO (K901) INLET AIR PRESSURE SENSOR GROUND CIRCUIT

Measure the resistance between the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit and the (K901) Inlet Air Pressure Sensor Ground circuit in the Inlet Air Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 5NoRepair the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit for a short to the (K901) Inlet Air Pressure Sensor Ground circuit.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)5. (K668) INLET AIR PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit between the Inlet Air Pressure Sensor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 10NoRepair the (K668) Inlet Air Pressure Sensor 5 Volt Supply circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)6. INLET AIR PRESSURE SENSORTurn the ignition on.With the scan tool, Clear DTCs.With the scan tool, select View DTCs.The scan tool should display an Inlet Air Pressure Sensor high voltage or open DTC with the Inlet Air Pressure Sensor connector disconnected.Does the scan tool display the DTC(s) as described above?YesReplace the Inlet Air Pressure Sensor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 77. (K68) INLET AIR PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND

Turn the ignition off.Disconnect the Engine Control Module (ECM) harness connector.Measure the resistance between ground and the (K68) Inlet Air Pressure Sensor Signal circuit in the Inlet Air Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 8NoRepair the (K68) Inlet Air Pressure Sensor Signal circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)8. (K68) INLET AIR PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO (K901) INLET AIR PRESSURE SENSOR GROUND CIRCUIT

Measure the resistance between the (K68) Inlet Air Pressure Sensor Signal circuit and the (K901) Inlet Air Pressure Sensor Ground circuit in the Inlet Air Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 9NoRepair the (K68) Inlet Air Pressure Sensor Signal circuit for a short to the (K901) Inlet Air Pressure Sensor Ground circuit.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)9. (K68) INLET AIR PRESSURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K68) Inlet Air Pressure Sensor Signal circuit between the Inlet Air Pressure Sensor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 10NoRepair the (K68) Inlet Air Pressure Sensor Signal circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)10. ENGINE CONTROL MODULE (ECM)Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Inlet Air Pressure Sensor and the Engine Control Module (ECM).Look for any chafed, pierced, pinched, or partially broken wires.Look for broken, bent, pushed out or corroded terminals.Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.Look for the data to change or for the DTC to reset during the wiggle test.Refer to any Technical Service Bulletins that may apply.Were any problems found?YesRepair as necessary.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoReplace the Engine Control Module (ECM) in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)