Chevrolet Silverado / GMC Sierra. Service manual — part 1832

Tighten: Tighten the nuts to 95 N.m (70 lb ft).

17. Remove the support from the transmission.

18. Lower the vehicle.

EXHAUST PARTICULATE FILTER CLEANING (LMM DPF REGENERATION ENABLE)

DPF Regeneration Enable

1. Ignition ON, clear all DTCs with a scan tool.

2. Select DPF Regeneration Enable within the Special Function menu.

3. Select ON.

The selection can be confirmed by the DPF Regeneration Reason parameter indicating
Device Control.

4. Exit the Special Function Menu. The scan tool can now be removed.

The vehicle will perform an active Regeneration as soon as the engine running conditions are met.

EXHAUST PARTICULATE FILTER CLEANING (LMM DPF SERVICE REGENERATION)

IMPORTANT: The DPF Regeneration Enable is required when specific service

procedures have been performed. Do not perform a DPF
Regeneration Enable unless instructed to in the Repair
Instruction section of the service procedure. After the system
repair perform the following to avoid possible damage to the DPF.

CAUTION: Tailpipe outlet exhaust temperature will be greater than 300°C

(572°F) during service regeneration. To help preven t personal
injury or property damage from fire or burns, perform the
following:

1. Do not connect any shop exhaust removal hoses to the

vehicle's tailpipe.

2. Park the vehicle outdoors and keep people, other

vehicles, and combustible material away during service
regeneration.

3. Do not leave the vehicle unattended.

CAUTION: To avoid extremely elevated exhaust temperatures, inspect

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Exhaust - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Conditions for Running

The following conditions must be met in order to enable DPF Service Regeneration:

There are no active DTCs displayed.

The battery voltage is greater than 10 volts.

The engine speed is between 600-1,250 RPM.

The exhaust gas temperature (EGT) sensors 1 and 2 are less than 400°C (752°F).

The engine coolant temperature (ECT) sensor 1 is between 70-115°C (158-239°F).

The brake pedal and accelerator pedal are in the released position.

The transmission is in Park or Neutral.

Test Procedure

1. Clear all DTCs with a scan tool before proceeding with DPF Service Regeneration.

2. Observe the scan tool DPF Regenerations Completed parameter and record the value.

3. Check the following fluid levels before and after this procedure:

Engine oil

Engine coolant

Power steering

Transmission

Fuel level should be over 15 percent to ensure a successful regeneration.

4. Park the vehicle outside the facility, away from any obstacles, place the transmission in Park

and apply the parking brake.

5. Ensure the hood is open.

6. Select DPF Service Regeneration in the Output Controls menu and follow the instruction on

and remove any debris or mud build up at the exhaust cooler
located at the tailpipe.

NOTE:

Due to the elevated engine temperatures created while performing
this procedure it is imperative to keep the front of vehicle in an
open environment, with the hood open, away from any walls or
buildings. This will ensure proper airflow across the radiator.

IMPORTANT: Do not refuel the vehicle during DPF Service Regeneration.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Exhaust - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

the scan tool.

7. Command the DPF Service Regeneration with the scan tool.

8. The DPF Service Regeneration will take approximately 35 minutes consisting of the

following:

1. 8 minutes for the exhaust system to warm up, with the engine speed slowly increasing

to 1,600 RPM, then 2,200 RPM and finally 2,500 RPM

2. 20 minutes for the DPF to regenerate at 2,500 RPM

3. 3 minutes for the exhaust system to cool down with the engine speed will slowly

returning to 1,400 RPM

4. 3 minutes at 800 RPM, then idle speed of 680 RPM

9. The DPF Service Regeneration will be terminated if any of the following actions are

performed:

Applying the brake pedal

Applying the accelerator pedal

Selecting Drive or Reverse

Commanding DPF Service Regeneration OFF using the scan tool or disconnecting the
scan tool from the vehicle

10. After the service regeneration completes, allow the vehicle to idle for an additional 2

minutes while monitoring the scan tool DTC information. There should be no additional
DTCs setting.

If DTC P244B sets, replace the Exhaust Particulate Filter.

If service regeneration aborted or failed, repair the vehicle for the condition indicated
by the scan tool DPF Regen Inhibit Reason parameter. Refer to the Service
Regeneration Fault Table below.

11. Ignition OFF for 90 seconds, perform the following within 10 minutes of a completed

service regeneration. Operate the vehicle within the following conditions to run the DTC.
Refer to DTC P2002 .

If DTC P2002 sets, replace the Exhaust Particulate Filter.

IMPORTANT:

The DPF Service Regeneration will be automatically
terminated if certain DTCs are set or if the DPF or ECT
temperatures exceed a calibrated threshold.

Temporary blue, gray, or white smoke during this
procedure may be an indication of a fuel with high sulfur
content.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Exhaust - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

12. Verify that the scan tool DPF Soot Mass parameter is less than 10 grams.

If greater than the specified range, refer to Service Regeneration Unsuccessful.

13. Verify that the scan tool DPF Regenerations Completed parameter has increased by one.

If the value has not increased by one, refer to Service Regeneration Unsuccessful.

Service Regeneration Unsuccessful

The scan tool DPF Regen Inhibit Reason parameter, will display a reason for not enabling
DPF Service Regeneration. Refer to the parameters that are displayed.

The scan tool DPF Regeneration Status parameter will display Active or Required
depending on the current commanded state of regeneration.

The scan tool DPF Regenerations Completed parameter did not increment.

The scan tool DPF Soot Mass parameter, will display greater than 10 grams, indicating
excessive particulate matter is still present in the filter.

Service Regeneration Status Fault Table

EXHAUST PARTICULATE FILTER REPLACEMENT (6.6L - PICKUP)

Removal Procedure

DPF Regeneration

Parameters

Successful Regeneration

Unsuccessful Regeneration

DPF Regeneration Status

Complete

Active or Required

DPF Regeneration Reason

None

Fuel Used

Engine Run Time

Distance Traveled

DPF Pressure

Soot Mass

Calculated Soot

DPF Regeneration Inhibit
Reason

None

Varies

DPF Soot Mass

Less than 10 grams

Greater than 10 grams

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Exhaust - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado