Diesel Particle Filter (DPF): Testing and Inspection

Diesel Particulate Filter (DPF) Increased Particle Mass, Checking

Observe all safety precautions: => [ Safety Precautions ] Safety Precautions

View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions

Prior to repair work, perform a preliminary check to verify the condition. Refer to => [ Preliminary Check ] Preliminary Check.

This diagnostic involves reading values with a scan tool and performing a visual inspection of suspected areas.

Special tools, testers and auxiliary items required

• Generic scan tool

• The Diesel Particulate Filter will require a periodic replacement. This is normal. The Regeneration process will produce an ash residue that over time will build up in the DPF causing a permanent restriction. Filter replacement will be necessary. If the DPF requires frequent replacement, follow the list of possible causes below to determine the cause of excessive sooting.

Possible Causes, Air intake system:

• Mass Air Flow sensor reading inaccurate.

• Restricted air filter.

• Leak in intake duct (before or after turbo).

• Throttle valve mechanical fault or inaccurate reading.

• Intake manifold flap mechanical fault or inaccurate reading.

• Turbocharger actuator mechanical fault or Charge Air Pressure sensor inaccurate reading.

• EGR leak from faulty actuator.

• Intake ports restricted.

Possible Causes, Fuel supply and injection system:

• Restricted fuel filter.

• Incorrect fuel blend (gelling).

• Fuel rail pressure sensor or pressure control valve faulty.

• Stuck fuel injector (open).

• High pressure fuel pump faulty.

Possible Causes, Exhaust gas control system:

• Oxygen sensor reading inaccurate.

• Exhaust temperature sensor faulty

Possible Causes, Other system causes:

• Excessive oil in combustion chamber due to:

• Worn piston rings.

• Leaking cylinder head gasket.

• Oil entering the turbocharger via the EGR valve due to excessive blow by in the crankcase.

- Repair any fault or mechanical failure found during above inspection/scan tool comparison check.

Final procedures

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.