The diesel particulate filter (DPF) captures diesel exhaust particulates, preventing their release into the atmosphere. When a high particulate loading condition occurs, the engine control module (ECM) will command a regeneration event to restore the DPF. If regeneration does not occur, the ECM will illuminate the DPF warning indicator. If the DPF indicator is ignored, the ECM will illuminate the MIL and revert to reduced engine power. Manual regeneration can be accomplished by pressing the DPF regeneration switch. During regeneration, the green DPF indicator will illuminate. The other DPF warning indicator will illuminate yellow when regeneration is required. When the same indicator turns red, immediate attention is required.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

Scan Tool Reference

Scan Tool Data List

1. Ignition ON, verify that the DPF indicators illuminate during the self test when the ignition is turned ON.

⇒	If either, or both the indicators do not illuminate, replace the IPC.

2. Ignition OFF, disconnect the harness connector at the diesel particulate filter (DPF) regeneration switch.
3. Ignition OFF, test for less than 1.0 ohm of resistance between the DPF regeneration switch ground circuit and ground.

⇒	If greater than 1.0 ohm, test the ground circuit for an open/high resistance.

4. Ignition ON, verify that the scan tool DPF Indicator Command is Off.

⇒	If not Off, test the DPF regeneration switch signal circuit for a short to ground. If the circuit tests normal, replace the IPC.

5. Install a 3-amp fused jumper wire between the DPF regeneration switch signal circuit and ground. Verify that the scan tool DPF Indicator Command Indicator is On.

⇒	If not On, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.