For a complete wiring diagram Refer to Section 8WThe Diesel particulate filter is an inline canister filter located in the exhaust system between the engine and the muffler. This filter captures and stores ash particles created by the diesel combustion process. This filter is monitored by the ECM with a Differential Pressure Sensor. This sensor measures the difference in exhaust system pressure before and after the particulate filter through tube connections directly to the exhaust pipe. As ash and soot accumulate in the filter, the exhaust pressure at the inlet side of the filter increases as compared to the pressure at the outlet side of the filter. When Monitored:With the ignition on.Set Condition:The (K355) Exhaust Differential Pressure Sensor signal is below 0.15 volts for 0.5 second.Possible CausesINTERMITTENT DTC(K354) EXHAUST DIFFERENTIAL PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND(K355) EXHAUST DIFFERENTIAL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND(K354) EXHAUST DIFFERENTIAL PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO (K951) EXHAUST DIFFERENTIAL PRESSURE SENSOR GROUND CIRCUIT(K355) EXHAUST DIFFERENTIAL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO (K951) EXHAUST DIFFERENTIAL PRESSURE SENSOR GROUND CIRCUIT(K354) EXHAUST DIFFERENTIAL PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE(K355) EXHAUST DIFFERENTIAL PRESSURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCEEXHAUST DIFFERENTIAL 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. (K354) EXHAUST DIFFERENTIAL PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT VOLTAGE

Turn the ignition off.Disconnect the Exhaust Differential Pressure Sensor harness connector.Turn the ignition on.Measure the voltage of the (K354) Exhaust Differential Pressure Sensor 5 Volt Supply circuit in the Exhaust Differential Pressure Sensor harness connector.Is the voltage above 4.5 volts?YesGo to 6NoGo to 33. (K354) EXHAUST DIFFERENTIAL PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO GROUND

Turn the ignition off.Disconnect the Engine Control Module (ECM) harness connector.Measure the resistance between ground and the (K354) Exhaust Differential Pressure Sensor 5 Volt Supply circuit in the Exhaust Differential Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 4NoRepair the (K354) Exhaust Differential 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. (K354) EXHAUST DIFFERENTIAL PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT SHORTED TO (K951) EXHAUST DIFFERENTIAL PRESSURE SENSOR GROUND CIRCUIT

Measure the resistance between the (K354) Exhaust Differential Pressure Sensor 5 Volt Supply circuit and the (K951) Exhaust Differential Pressure Sensor Ground circuit in the Exhaust Differential Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 5NoRepair the (K354) Exhaust Differential Pressure Sensor 5 Volt Supply circuit for a short to the (K951) Exhaust Differential Pressure Sensor Ground circuit.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)5. (K354) EXHAUST DIFFERENTIAL PRESSURE SENSOR 5 VOLT SUPPLY CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K354) Exhaust Differential Pressure Sensor 5 Volt Supply circuit between the Exhaust Differential Pressure Sensor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 10NoRepair the (K354) Exhaust Differential 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. (K355) EXHAUST DIFFERENTIAL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO GROUND

Turn the ignition off.Disconnect the Engine Control Module (ECM) connector.Measure the resistance between ground and the (K355) Exhaust Differential Pressure Sensor Signal circuit in the Exhaust Differential Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 7NoRepair the (K355) Exhaust Differential Pressure Sensor Signal circuit for a short to ground.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)7. (K355) EXHAUST DIFFERENTIAL PRESSURE SENSOR SIGNAL CIRCUIT SHORTED TO (K951) EXHAUST DIFFERENTIAL PRESSURE SENSOR GROUND CIRCUIT

Measure the resistance between the (K355) Exhaust Differential Pressure Sensor Signal circuit and the (K951) Exhaust Differential Pressure Sensor Ground circuit in the Exhaust Differential Pressure Sensor harness connector.Is the resistance above 1000 ohms?YesGo to 8NoRepair the (K355) Exhaust Differential Pressure Sensor Signal circuit for a short to the (K951) Exhaust Differential Pressure Sensor Ground circuit.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)8. (K355) EXHAUST DIFFERENTIAL PRESSURE SENSOR SIGNAL CIRCUIT OPEN OR HIGH RESISTANCE

Measure the resistance of the (K355) Exhaust Differential Pressure Sensor Signal circuit between the Exhaust Differential Pressure Sensor harness connector and the Engine Control Module (ECM) harness connector.Is the resistance below 10.0 ohms?YesGo to 9NoRepair the (K355) Exhaust Differential Pressure Sensor Signal circuit for an open circuit or high resistance.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)9. EXHAUST DIFFERENTIAL PRESSURE SENSOR

Turn the ignition off.Connect the Engine Control Module (ECM) harness connector.Connect a jumper wire between the (K354) Exhaust Differential Pressure Sensor 5 Volt Supply circuit and the (K355) Exhaust Differential Pressure Sensor Signal circuit in the Exhaust Differential Pressure Sensor harness connector.Turn the ignition on.With the scan tool, Clear DTCs.With the scan tool, select View DTCs.The scan tool should display an Exhaust Differential Pressure Sensor high voltage or open DTC with the Exhaust Differential Pressure Sensor harness connector disconnected and the jumper wire in place.Does the scan tool display the DTC as described above?YesReplace the Exhaust Differential Pressure Sensor in accordance with the Service Information.Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)NoGo to 1010. ENGINE CONTROL MODULE (ECM)Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Exhaust Differential 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)