For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Diesel Particulate Filter is an in-line canister filter located in the exhaust system between the engine and the muffler. This filter captures and stores soot particles created by the diesel combustion process. 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. This filter is monitored by the PCM with a Differential Pressure Sensor. There is a tube at the inlet and outlet of the Diesel Particulate Filter. A hose is attached to each tube. The other end of the hose is connected to the Differential Pressure Sensor. The Differential Pressure Sensor compares the pressure from each hose and measures the delta pressure (difference between the inlet and outlet) in the Diesel Particulate Filter.
When Monitored:
With the engine running.
Set Condition:
The Differential Pressure Sensor signal indicates partial clogging of the particulate filter due to the accumulation of ash or other debris.
Possible Causes
DAMAGED EXHAUST SYSTEM
LEAKING EXHAUST SYSTEM
HIGH RESISTANCE IN EXHAUST DIFFERENTIAL PRESSURE SENSOR CIRCUITS
HOSE/TUBE CONNECTIONS TO THE EXHAUST DIFFERENTIAL PRESSURE SENSOR
Visually inspect the Exhaust Differential Pressure Sensor for physical damage, proper electrical connection and proper mechanical connection. Ensure any tubes and/or hoses connected to the sensor are in good working condition and properly connected at all ends.
3.
Visually inspect the entire exhaust system for bent, crushed or otherwise damaged tubes which may cause an exhaust system restriction.
3.
CHECK THE EXHAUST DIFFERENTIAL PRESSURE SENSOR CIRCUITS FOR HIGH RESISTANCE
1.
Turn the ignition off.
2.
Disconnect the Exhaust Differential Pressure Sensor harness connector.
3.
Disconnect the PCM C1 harness connector.
4.
Measure the resistance of each Exhaust Differential Pressure Sensor circuit between the Exhaust Differential Pressure Sensor harness connector and the PCM C1 harness connector.
Is the resistance below 5.0 Ohms for each circuit?
