2000 - 2999: 2626

2626-DIESEL PARTICULATE FILTER - SOOT CONTENT TOO HIGH

For a complete wiring diagram Consult Diagrams/Electrical

Theory of Operation

The 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 accumulates 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. The ECM monitors the sensor to determine when to perform a particulate filter regeneration procedure which is designed to clear or "burn-off" the ash collected in the 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.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. VISUAL INSPECTION
Turn the ignition off.
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.
Visually inspect the entire exhaust system for bent, crushed or otherwise damaged tubes which may cause an exhaust system restriction.
Inspect the exhaust system for exhaust leaks.
Were any problems found?

Yes

- Repair or replace as necessary.

No

- Go To 2

2. PARTICULATE FILTER REGENERATION
Start and idle the engine.
With the scan tool, Clear DTCs in the Engine Control Module (ECM).
With the scan tool, perform the Diesel Particulate Filter Regeneration procedure.
After this procedure is complete, turn the ignition off for 60 seconds.
Test drive the vehicle.
With the scan tool, Read DTCs in the Engine Control Module (ECM).
Is the status Active for this DTC?

Yes

- Go To 3

No

- Test complete.

3. EXHAUST DIFFERENTIAL PRESSURE SENSOR CIRCUIT HIGH RESISTANCE
Turn the ignition off.
Disconnect the Exhaust Differential Pressure Sensor harness connector.
Disconnect the ECM harness connectors.
Measure the resistance of each Exhaust Differential Pressure Sensor circuit between the Exhaust Differential Pressure Sensor harness connector and the ECM harness connector.
Is the resistance below 10.0 ohms for each circuit?

Yes

- Go To 4

No

- Repair the circuit(s) that measured above 10.0 ohms for high resistance.

4. EXHAUST DIFFERENTIAL PRESSURE SENSOR
Turn the ignition off.
Replace the Exhaust Differential Pressure Sensor.
Turn the ignition on.
With the scan tool, Clear DTCs in the Engine Control Module (ECM).
Test drive the vehicle
With the scan tool, Read DTCs in the Engine Control Module (ECM).
Is the status Active for this DTC?

Yes

- Replace the Diesel Particulate Filter.

No

- Test Complete.