6.6l duramax: lgh and lml diesel engines 14, 2011 · 6.6l duramax: lgh and lml diesel engines how...

© 2011 General Motors Company, All Rights Reserved

Course Number: S-EP08-03.01VCT

6.6L Duramax: LGH and LML Diesel Engines

Participant Guide Revised: 09/14/11

Caution

Danger: In order to reduce the chance of death, personal injury and/or property damage, carefully observe the instructions that follow:

The service manuals of General Motors Company are intended for use by professional, qualified technicians. Attempting repairs or service without the appropriate training, tools, and equipment could cause death or injury to you or others. This could also damage the vehicle, or cause the vehicle to operate improperly.

Proper vehicle service and repair are important to the safety of the service technician and to the safe, reliable operation of all motor vehicles. If you need to replace a part, use the same part number or an equivalent part. Do not use a replacement part of lesser quality.

The service procedures we recommend and describe in this service manual are effective methods of performing service and repair. Some of the procedures require the use of tools that are designed for specific purposes.

Accordingly, any person who intends to use a replacement part, a service procedure, or a tool that is not recommended by General Motors, must first establish that there is no jeopardy to personal safety or the safe operation of the vehicle.

This manual contains various "Dangers", "Warnings" and "Cautions" that you must observe carefully in order to reduce the risk of personal injury during service or repair. Improper service or repair may damage the vehicle or render the vehicle unsafe. These Dangers, Warnings, and Cautions are not exhaustive. General Motors cannot possibly warn of all the potentially hazardous consequences of your failure to follow these instructions.

This manual covers service procedures to vehicles that are equipped with a Supplemental Inflatable Restraint. Refer to the "Warnings" in Dangers, Warnings and Cautions in Supplemental Inflatable Restraint. Refer to Supplemental Inflatable Restraint component and wiring location views in Supplemental Inflatable Restraint before performing a service on or around Supplemental Inflatable Restraint components or wiring. Failure to follow these Dangers, Warnings, and "Cautions could cause air bag deployment, personal injury, or otherwise unnecessary Supplemental Inflatable Restraint repairs.

In order to help avoid accidental air bag deployment and personal injury, whenever you service a vehicle that requires repair of the Supplemental Inflatable Restraint and another vehicle system, we recommend that you first repair the Supplemental Inflatable Restraint, then go on to the other system.

June 2008

6.6L Duramax: LGH and LML Diesel Engines How to Complete the Audio Setup Wizard

AW-1

How to Complete the Connect Audio Setup Wizard –

Participants


AW-2

How to Complete the Connect Audio Setup Wizard

Once you have launched the course, select Meetings > Manage My Settings > Audio Setup Wizard

Click Next.

Click Test. Follow the directions. Click Next.


AW-3

Choose your microphone or sound card from the drop-down list. Click Next.

Click Record. Follow the directions. Click Next.


AW-4

Click Test Silence. Stay silent until the test is finished. Click Next.

Click Finish.

6.6L Duramax: LGH and LML Diesel Engines Table of Contents

TC-1

Table of Contents

Introduction ................................................................................... i-1

Module 1: Fuel Return System Diagnosis ............................................. 1-1

Module 2: Exhaust Aftertreatment Fuel Injector Performance .............. 2-1

Module 3: Reductant Pump Control Circuit ........................................... 3-1

Module 4: Diesel Exhaust Fluid System Diagnosis ................................ 4-1

Module 5: Incorrect Reductant Composition ......................................... 5-1

Instructor Name:

Help Number: 800-825-5886, prompt 1

This manual contains information about service for the 6.6L Duramax LGH and LML diesel engines and their components. Always refer to applicable vehicle service information and appropriate Dealer Technical Service Bulletins for additional information regarding system operation and diagnostic/repair procedures. When this manual refers to a brand name, a number, or a specific tool, you may use an equivalent product in place of the recommended item.

All information, illustrations and specifications in this manual are based on the latest product information available at the time of publication approval. General Motors reserves the right to make changes at any time without notice.

No part of this book may be reproduced, stored in any retrieval system, or transmitted in any form or by any means (including but not limited to electronic, mechanical, photocopying, and recording) without prior written permission of General Motors Company. This applies to all text, illustrations, tables and charts. © 2011

6.6L Duramax: LGH and LML Diesel Engines Introduction

i-1

Introduction

6.6L Duramax: LGH and LML Diesel Engines Introduction

i-2

Welcome to 6.6L Duramax: LGH and LML Diesel Engines

Course Goal

Upon completion of this course, you will be able to apply concepts and procedures to diagnose and service concerns on the 6.6L Duramax Diesel engine and its components.

Session 3 Objectives

Describe Fuel System Return Side diagnostic procedures Describe Exhaust Aftertreatment Fuel Injector Performance diagnostic procedures Describe Reductant Pump Control Circuit diagnostic procedures Describe Diesel Exhaust Fluid System diagnostic procedures Describe Incorrect Reductant Composition diagnostic procedures

Strategy Based Diagnosis

Step 1. Understand and verify the customer concerns

Step 2. Check that the vehicle is operating as designed

Step 3. Conduct the Preliminary Checks-visual and operational

Step 4. Perform the Diagnostic System Check-Vehicle

Step 5. Check the Bulletins, Recalls and Preliminary Information

Step 6. Perform the Diagnostics

Step 7. Re-examine the Concern

Step 8. Repair and Verify the Fix

Special Instructions

The diagnostic charts in this courseware are for reference only. Refer to Service Information when servicing the 6.6L Duramax diesel engine and its components.


MODULE 1 Fuel Return System Diagnosis

6.6L Duramax: LGH and LML Diesel Engines Module 1: Fuel Return System Diagnosis

1-2

Module 1 Objective

At the end of this module, you will be able to diagnose Fuel System Return Side concerns on the 6.6L Duramax diesel engine.

NOTE: Refer to Service Information for correct procedures when diagnosing concerns on the 6.6L Duramax diesel engine or its components.

Diagnostic Scenario

2011 Chevrolet Silverado Duramax LML engine

A customer’s 2011 Chevrolet Silverado was towed into the dealership.

The customer indicated that the engine cranks but that it would not run

Preliminary Diagnosis:

Strategy Based Diagnosis (SBD) Service Information, and then Diagnostic System Check–Vehicle Engine Cranks But Does Not Run


1-3

Engine Cranks But Does Not Run

Service Information

Diagnostic Aids

If the engine cranks but does not run condition occurs only in cold ambient temperatures, it may be due to ice blockage at the fuel pickup in the fuel tank--This will be indicated by a high vacuum in the supply lines while cranking and the problem will disappear after the vehicle is brought into the service bay. This condition may also cause the vehicle to start and stall, or to start but have no acceleration.

Circuit/System Verification

1. If DTCs P0090, P0191, P0192, P0193, P0335, P0336, P0340, P0601, P0602, P0606, P0609, P060B, P061C, P062F, P0641, P064C, P0651, P0697, P06A3, P06D2, P2510, or P2610 are set, diagnose those DTCs first.

2. Ignition ON, observe the scan tool VTD Fuel Disable parameter. The parameter should display INACTIVE.

If the VTD Fuel Disable parameter displays ACTIVE, perform the Immobilizer System Component Programming.

3. Engine cranking, observe the scan tool Engine Speed parameter. The minimum cranking speed is 80 RPM on a cold engine and 125 RPM on a hot engine.

If the cranking speed is slow, refer to Engine Cranks Slowly

If the engine speed is 0 RPM, refer to DTC P0335 or DTC P0336 for further diagnosis.

4. Inspect for the following conditions:

• Inadequate fuel in the fuel tanks.

• Fuel smell or leak--Refer to Fuel Leak Diagnosis.

• Fuel contamination--Refer to Contaminants-in-Fuel Diagnosis.

• A collapsed air intake duct or restricted air filter element.

5. Install the CH-48027 to the fuel rail service port. Engine cranking, verify the fuel pressure gauge displays between 1-6 in. Hg.

If the value displayed is not within the specified range, refer to Fuel System Diagnosis.

6. Engine cranking, verify the scan tool Fuel Rail Pressure Sensor parameter is greater than 10 MPa.

If less than the specified range, refer to Fuel System Diagnosis - High Pressure Side.

7. Verify the operation of the fuel system constant pressure regulator--Refer to Fuel Return System Diagnosis. Perform steps 6-9.


1-4

Engine Cranks But Does Not Run (continued)

Constant Pressure Regulator

On LGH and LML engines, the high voltage Piezo injectors require that the return side of the Fuel System is pressurized for proper operation.

The constant pressure regulator maintains return side pressure between 0.4 to 1.1 MegaPascals (MPa) or 58 to 160 pounds per square inch (psi).

Notes: _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________


1-5

Fuel Return System Diagnosis

Service Information

Diagnostic Aids

Bent or pinched fuel return lines may cause an external fuel leak or engine performance concerns.

Low injector return line pressure may cause a No-Start condition.

Low injector return line pressure may cause performance concerns.

Contaminated fuel or improper fuel may cause engine performance concerns.

Circuit/System Testing

Note: DO NOT apply more than the specified air pressure to the return line.

6. Disconnect a fuel injector return line and place the end into a suitable container.

Note: A small amount of fuel will leak out of the fuel injector return fitting. Place a lint free towel around the injector to prevent fuel leakage.

7. Crank the engine for 5 seconds, verify fuel flow is present.

If no fuel flows into the container, check the fuel feed line for kinks or restrictions. If the fuel feed line tests normal, refer to Fuel System Diagnosis.

Note: Idle the engine for 2 minutes to allow pressure to build in the injector return lines. If the vehicle is a No-Start, it may be necessary to crank the engine several times in order to build pressure.

8. Install the CH-50375 and gauge on an injector return line. Crank or start the engine and verify that the fuel pressure is greater than 4 bar (58 psi).

If less than the specified value, replace the constant pressure regulator.

9. Run the engine at 2000 RPM for 2 minutes and verify the return line fuel pressure is less than 14 bar (200 psi).

If greater than the specified value replace the constant pressure regulator.


1-6

Video: Fuel System Return Line Testing

The Engine Cranks But Does Not Run diagnostics in Service Information direct us to verify that the fuel rail pressure sensor reads greater than 10 MegaPascals (MPa), or 1450 pounds per square inch (psi), when the engine is cranking.

In our case, everything looks good. Service Information then directs us to Fuel Return System diagnosis.

Begin by inspecting the fuel return hoses and lines on the engine and chassis for any signs of leaks, pinched areas or damage. No damage is found, so we will continue on to step 6 in the diagnosis. We have already verified that the fuel rail pressure sensor reads greater than 10 MPa or 1450 psi.

SI now directs us to remove the return line from an injector.

Pressure Greater than 10 Mpa (1450 psi)

To disengage the fuel return line, pull upward on the cylindrical locking sleeve and remove the line.

Place the end of the fuel return line in a suitable container.

Crank the engine for 5 seconds to verify there is fuel flow.

Note: A small amount of fuel may leak out of the fuel injector return fitting. To prevent fuel leakage, place a lint-free towel around the injector.

Fuel flow in container—verified


1-7

Video: Fuel System Return Line Testing (continued)

Since there is fuel flow, SI directs us to install the CH 50375 Fuel Injector Return Line Adapter, and a pressure gauge on an injector return line.

Crank the engine several times to verify the pressure reads greater than 0.4 MPa (58 psi). In our case, we have no return side pressure.

Installing CH 50375 Fuel Injector Return Line Adapter

The constant pressure regulator will need to be replaced.

The final step is to crank the engine and verify that it now starts and runs.

Constant pressure regulator

Notes: _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________


1-8

Fuel Return System Diagnosis (continued)

Bosch Piezo High Voltage Fuel Injector

A hydraulic coupling is inside the Bosch high voltage Piezo injectors.

Bosch Piezo High Voltage Fuel Injector

For proper operation, there must be

0.4 to 1.1 MPa (58-160 psi) of pressure on the Return Side of the injector.

The Piezo crystal stack acts upon this coupler to control the nozzle of the injector.

Without this hydraulic coupling, the nozzle will not open and inject fuel into the cylinder.

Return Side pressure greater than 0.4 MPa (58 psi)


1-9


Return Line Service Procedure To remove the return line from the injector: Lift the center section to release

tension on the tabs; remove the line.

Return line—released

Inspect the tabs of the return line connection for breakage.

Return line tabs To install the return line: Insert the line onto the injector until it

clicks, and then press the center section down.

Check the line connection by pulling up slightly on the line assembly.

If the line pulls off the injector, you’ll need to repeat the procedure.

Return line—secured


1-10


Fuel System Priming

The high voltage Piezo injection system is more difficult to prime than on previous Duramax engines.

To aid in starting when the Fuel System is serviced, there is a backfill valve on the return side.

The valve is fed by a pressure line that is mounted between the supply pump and the high pressure pump.

When return side pressure drops below 0.4 MPa (58 psi), the valve will open to pressurize the return side.

Backfill valve

Diagnostic Repair Verification To verify the repair, crank the engine and verify that it starts and runs. Then, inspect the return hoses for any leaks. The engine starts and runs, and no leaks were found.


1-11

Module 1 Summary

Diagnosed Fuel System Return Side—Engine Cranks But Does Not Run: ─ Fuel return system diagnosis

─ Constant pressure regulator

─ Return line service

─ Fuel system priming

─ Repair verification


MODULE 2 Exhaust Aftertreatment Fuel Injector

Performance

6.6L Duramax: LGH and LML Diesel Engines Module 2: Exhaust Aftertreatment Fuel Injector Performance

2-2

Module 2 Objective

At the end of this module, you will be able to diagnose an Exhaust Aftertreatment Fuel Injector Performance concern on the 6.6L Duramax diesel engine.


Diagnostic Scenario

2011 Chevrolet Silverado Duramax engine

2011 Chevrolet Silverado into the dealership.

Malfunction Indicator Lamp (MIL) was illuminated.

ENGINE POWER IS REDUCED was displayed in the Driver Information Center (DIC).


Strategy Based Diagnosis (SBD) Diagnostic Information and Procedures Diagnostic System Check–Vehicle Diagnostic Trouble Code (DTC) List—Vehicle DTC P20CC found set


2-3

DTC P20CC

DTC P20CC is for Exhaust Aftertreatment Fuel Injector performance. The Exhaust Aftertreatment Fuel Injector is also called the Hydrocarbon Injector

(HCI). The Engine Control Module (ECM) monitors the Exhaust Gas Temperature (EGT)

sensors. If the difference between EGT 1 and 2 or EGT 3 and 4 is greater than 300°C (540°F)

when the vehicle is not in regeneration, this code will set. For this DTC type, the ECM commands the engine to operate in Reduced Engine

Power mode.

Notes: _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________


2-4

DTC P20CC (continued)

Service Information

Conditions for Running the DTC

• Engine speed is greater than 600 RPM.

• Exhaust temperature is greater than 300°C (572°F).

• Time since last completed regeneration is greater than 15 minutes.

• Time since last indirect fuel injector nozzle cleaning request is greater than 5 minutes.

Action Taken When the DTC Sets

• DTC P20CC is a Type A DTC.

• The ECM commands the engine to operate in the Reduced Engine Power mode.

• The message center displays Reduced Engine Power.

Diagnostic Aids

• Skewed exhaust temperature sensors may cause this DTC to set.

• An indirect fuel injector that is stuck open or leaking may cause this DTC to set.

• Contaminated fuel may cause this DTC to set.


1. Engine running, observe the following scan tool parameters:

• EGT Sensor 1

• EGT Sensor 2

• EGT Sensor 3

• EGT Sensor 4

Each parameter should be within 300°C (540°F) of each other.

2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.


2-5

Video: DTC P20CC/HCI Diagnosis

Start the diagnosis with the Cylinder Power Balance test.

No erratic results are observed.

Cylinder Power Balance test screen

Remove the nozzle of the Hydrocarbon Injector (HCI) from the exhaust.

Install a piece of hose to the nozzle and place the other end in a suitable container.

Service Information directs us to start the engine and look for any fuel leaking from the HCI nozzle into the container. In our case, fuel is leaking.

HCI hose and nozzle in suitable container

We are directed to replace the HCI.

After removing the retaining bolts, use special tool CH 49736, the Hydrocarbon Injector Quick Connect Release Tool, to release the supply line from the injector, and then remove the assembly.

After installing the new HCI assembly, follow the repair verification procedure detailed in Service Information.


2-6

DTC P20CC (continued)

Diagnostic Repair Verification

If the scan tool DPF Soot Mass is less than 30 grams, perform the scan tool Diesel Particulate filter (DPF) Regeneration Enable procedure.

If the scan tool DPF Soot Mass is 30 grams or greater, perform the Diesel Particulate Filter (DPF) Service Regeneration procedure.

Hydrocarbon Injector The Hydrocarbon Injector (HCI) will

need to be purged of air after it has been removed or replaced.

It will also need to be purged if a repair procedure is performed that requires the injector supply line to be removed from the injector.

If the injector is not purged, the residual fuel and air at the injector can cause coking and may cause the injector to stick.

To purge the air, initiate a DPF Regeneration Enable with the scan tool before the vehicle is returned to the customer.

During regeneration, the injector is activated sufficiently enough to purge the air from the injector and the lines.

HCI—off engine

HCI—mounted on engine


2-7

Module 2 Summary

Described DTC P20CC Exhaust Aftertreatment Fuel Injector Performance diagnosis ─ Reduced Engine Power concern

─ Diagnostic Repair Verification

─ HCI repair and service procedures


MODULE 3 Reductant Pump Control Circuit

6.6L Duramax: LGH and LML Diesel Engines Module 3: Reductant Pump Control Circuit

3-2

Module 3 Objective

At the end of this module, you will be able to diagnose a Reductant Pump Control Circuit concern on the 6.6L Duramax diesel engine.


Diagnostic Scenario

2010i GMC Savana DEF warning indicator

The customer brought a 2010i GMC Savana into the dealership.

The Diesel Exhaust Fluid (DEF) warning message SERVICE EXHAUST FLUID SYSTEM was displayed in Instrument Panel Cluster (IPC).


Strategy Based Diagnosis (SBD) Diagnostic System Check–Vehicle Diagnostic Trouble Code (DTC) List—Vehicle DTC P208A found set


3-3

Selective Catalytic Reduction

The SCR system reduces nitrogen oxides (NOx) emissions by injecting a metered amount of DEF or reductant into the exhaust gas stream that enters the SCR catalyst.

Within the SCR catalyst, the DEF reacts with the NOx to form nitrogen, carbon dioxide, and water vapor.

Upstream and downstream NOx sensors provide the engine control module (ECM) with engine-out and tailpipe-out NOx levels.

The ECM regulates the amount of DEF added by varying the reductant injector duty cycle in response to changes in engine-out NOx levels.

Notes: _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________

DEF Injected into Exhaust Gas Stream

SCR Catalyst converts Ammonia/NOx mix to

Nitrogen, Carbon Dioxide, and Water


3-4

Diagnostic Scenario (continued)

NOTE: A component fault or several wiring faults could cause DTC P208A to set.

DTC P1043, P1044, P208A, P208C or P208DDiagnostic Fault Information

Circuit Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

DEF Smart Pump Supply Voltage

P208A P204F -- P208B

DEF Smart Pump Control P208A P208A P1044, P208D

P208B

DEF Smart Pump Low Reference

-- P208A -- P208B


3-5

DTC P1043, P1044, P208A, P208C or P208D

Service Information

Actions Taken When the DTC Sets

DTCs P1043, P1044, P208A, and P208D are Type B DTCs.

The ECM inhibits the reductant system when DTC P1043, P208A, or P208D is set.


1. Ignition ON, observe the DTC information with a scan tool. DTC P204B, P204C, or P204D should not be set.

If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

2. Observe the scan tool Reductant Pump Control Circuit Status parameter. The parameter should display OK or Not Run.

3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.


3-6

DTC P1043, P1044, P208A, P208C or P208D

Video: P208A Reductant Pump Control Diagnosis

Begin the diagnosis by disconnecting the 24-way harness connector at the diesel exhaust fluid (DEF) tank.

With the Ignition OFF for at least 2 minutes, test for less than 5 ohms between the low reference circuit, terminal C6 and ground, on the ECM side of the harness.

With the Ignition ON, test for battery voltage between the reductant pump motor supply voltage circuit, terminal A6 and ground.

Check for 2.5 to 4.5V between the reductant pump motor control circuit terminal B6 and ground.

Connect a test lamp between the reductant pump motor control circuit, terminal B6 and the reductant pump motor supply voltage circuit, terminal A6.

Command the Reductant Pump to 80 percent with the scan tool.

The test lamp should illuminate or flash when commanded to 80 percent. In our case the test lamp illuminates.

Test lamp illuminated at 80 percent


3-7

Video: P208A Reductant Pump Control Diagnosis (continued)

Since all of our tests have passed, remove the DEF tank and inspect the harness connector. We find a damaged terminal.

Replace the affected components and reinstall the DEF tank.

Harness connector damaged terminal

Finally, clear the DTCs, and perform the scan tool Reductant System Reset.

Notes: _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________


3-8

Video: Diagnostic Repair Verification

After clearing the DTC and

performing the Reductant System Reset with the scan tool, the Diesel Exhaust Fluid (DEF) lamp is still displayed on the Instrument Panel Cluster (IPC).

Diesel Exhaust Fluid lamp in IPC

The repair verification in Service Information indicates there are a number of steps that must be completed before returning the vehicle to the customer.

Install any components or connectors that have been removed during diagnosis.

Perform any necessary setup procedures, and clear any DTCs that are set.

With the ignition OFF, wait 2 minutes, then verify the DEF and ambient air temperatures are greater than negative 7°C (19°F).

DEF and ambient temperatures more than

-7°C (19°F).


3-9

Video: Diagnostic Repair Verification (continued)

Turn the ignition ON and command the Reductant System Leak test ON with the scan tool.

Allow the pressure to build for 30 seconds. The reductant pressure sensor should read between 425 to 575 kiloPascals (kPa), or 62 to 83 pounds per square inch (psi).

Inspect the system for leaks. Everything looks to be in order.

Allow the vehicle to reach operating temperature.

With the engine idling, accelerate at part throttle to 32 to 48 kilometers per hour, or 20 to 30 miles per hour for up to 5 minutes, or until the DEF lamp turns OFF.

DEF lamp On DEF lamp Off

NOTES: Permanent or “latched” DTCs are defined as a confirmed fault code that is stored in

non-volatile memory and currently commands the MIL to illuminate. This DTC prevents a vehicle from passing a Vehicle Inspection and Maintenance

programs (I/M) test by disconnecting the battery or with the scan tool to clear the code prior to inspection.

Permanent or “latched” DTCs can NOT be cleared by disconnecting the battery or with the scan tool prior to inspection.

Only the On-Board Diagnostic (OBD) II system can erase a permanent fault code. The system must determine if the malfunction that caused the permanent fault code

to be stored is no longer present. Follow the Repair Verification steps after making repairs.


3-10

Module 3 Summary

Described DTC P208A Reductant Pump Control Circuit diagnosis ─ SCR system operation

─ Clearing a “latched” DTC


MODULE 4 Diesel Exhaust Fluid System Diagnosis

6.6L Duramax: LGH and LML Diesel Engines Module 4: Diesel Exhaust Fluid System Diagnosis

4-2

Module 4 Objective

At the end of this module, you will be able to diagnose a Diesel Exhaust Fluid (DEF) System concern on the 6.6L Duramax diesel engine.


Diagnostic Scenario

2011 Chevrolet Silverado Duramax engine

Customer brought a 2011 Chevrolet Silverado into the dealership.

Diesel Exhaust Fluid (DEF) warning message SERVICE EXHAUST FLUID SYSTEM was displayed in Instrument Panel Cluster (IPC).

DEF warning indicator Preliminary Diagnosis:

Strategy Based Diagnosis (SBD) Diagnostic Information and Procedures Diagnostic System Check—Vehicle DTC P20EE found set


4-3

DTC P20EE NOTE: For DTC P20EE to set, the Engine Control Module (ECM) has determined that the catalyst efficiency has degraded below a calibrated threshold.

NOx Sensors

The ECM uses two nitrogen oxide (NOx) sensors to control exhaust NOx levels.

The NOx sensor measures the amount of NOx and oxygen in the exhaust system.

NOx Sensor 1 is located at the outlet of the turbocharger. NOx Sensor 1 monitors engine-out NOx.

NOx Sensor 2 is located in the canister between the selective catalytic reduction (SCR) and the diesel particulate filter (DPF). NOx Sensor 2 monitors NOx levels exiting the SCR.

The ECM responds to changes in engine exhaust-out NOx levels.

The ECM regulates the amount of DEF or reductant added by varying the reductant injector duty cycle.

NOx Sensor with Smart Module


4-4

Diesel Exhaust Fluid

For maximum NOx reduction

efficiency, the SCR system requires an adequate supply of clean pure DEF, or reductant.

The fluid is a mixture of 32.5% urea and 67.5% deionized water.

DEF that is designed for SCR systems should display the American Petroleum Institute (API) certification, or the International Organization for Standardization ISO 22241 certification.

Fresh DEF should be clear in color with a slight ammonia smell.

Notes: _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________


4-5

DTC P20EE (continued)

Service Information


1. Ignition ON, observe the DTC information with a scan tool. Verify there are no DTCs set related to the following systems or components:

• Diesel exhaust fluid system

• Engine misfire

• Exhaust gas recirculation

• Exhaust gas temperature sensors

• Fuel system - low or high pressure

• Indirect fuel injector

• Intake air flow valve

• MAF sensor

• NOx or HO2S sensors

• Turbocharger system


2. Test the diesel exhaust fluid for contamination. Refer to Contaminants-in-Diesel Exhaust Fluid Diagnosis.

Notes: _______________________________________________________________________

_______________________________________________________________________

_______________________________________________________________________


4-6

Video: Contaminants-in-Diesel Exhaust Fluid Diagnosis

During our P20EE diagnostics, Service Information directs us to perform the Contaminants-in-Diesel Exhaust Fluid (DEF) diagnosis.

Collect a sample of DEF from the tank by removing the DEF supply line on the injector and placing it in a clear container.

Command the pump ON. The DEF should be clear with no

obvious coloration when held up to a light.

The DEF sample should be odorless or have a slight ammonia smell.

In our case everything looks and smells good.

DEF sample in clear container

J 26568 Battery, Coolant and DEF Tester Placing DEF sample on tester

Service Information directs us to check the refractive index of the sample using the J 26568 Battery, Coolant and DEF Tester.

Place a sample of DEF on the tester.


4-7

Video: Contaminants-in-Diesel Exhaust Fluid Diagnosis (continued)

Using a strong light source to illuminate the scale, look through the eyepiece and

observe the scale on the J 26568.

The refractive index of pure DEF should be greater than 1.310. As we can see, our sample does not meet the specification.

Based on our results, Service Information directs us to drain the DEF tank and to refill it with fresh DEF.

DEF refractive index scale reading at 1.150 Observing scale on J 26568 Battery, Coolant and DEF Tester


4-8

Contaminants-in-Diesel Exhaust Fluid Diagnosis (continued)

Notes: Contamination of certain fluids can be identified by its color:

— Windshield washer solvent—orange or blue — Engine coolant—orange or green — Engine oil—brown — Transmission fluid—red or brown — Diesel fuel—clear, green, red, or brown

If the DEF sample has traces of visible contamination, follow Service Information for the proper repair procedures.

If no visible contamination, check the refractive index of the DEF sample.

Post Repair Procedures Perform scan tool procedures: NOx Catalyst Reductant Loading Reset Diesel Particulate Filter Service Regeneration Diesel Exhaust Fluid Quality Test

─ This test will reset the Reductant System history.


4-9

Video: Diesel Exhaust Fluid Quality Test

After replacing the Diesel Exhaust Fluid (DEF) during the DTC P20EE diagnosis, Service Information directs us to perform the Diesel Exhaust Fluid Quality Test.

WARNING: Tailpipe outlet exhaust temperature will be greater than 300°C (572°F) during this procedure.

To help prevent personal injury or property damage from fire or burns, perform the following: ─ Do not connect any shop exhaust removal hoses to the vehicle tailpipe. ─ Park the vehicle outdoors and keep people, other vehicles, and combustible

material away during this procedure. ─ Do not leave the vehicle unattended.

WARNING: To avoid extremely elevated exhaust temperatures, inspect and remove any debris or mud build up at the exhaust cooler located at the tailpipe.


4-10

Video: Diesel Exhaust Fluid Quality Test (continued)

With the ignition ON, verify that DTC P207F or P20EE are the only DTCs set.

Park the vehicle outside and away from any obstacles and open the hood.

Place the transmission in Park and apply the parking brake.

Clear the DTCs.

Vehicle outside with hood open

Check fluid levels before and after this

procedure. ─ Diesel exhaust fluid ─ Engine oil ─ Engine coolant ─ Power steering fluid ─ Transmission fluid

The fuel level should be at least 15 percent.

Check fluids


4-11

Video: Diesel Exhaust Fluid Quality Test (continued)

Command the Reductant Fluid Quality Test ON with the scan tool.

When a DEF quality test is commanded, the exhaust system is warmed up for about 8 minutes as the engine speed is slowly increased to 1900 RPM.

Once the Diesel Particulate Filter (DPF) reaches a calibrated temperature, the Engine Control Module (ECM) maintains engine speed at 1900 RPM for about 20 minutes until the quality test is complete.

The ECM then slowly decreases engine speed to the normal idle speed.

ECM engine speed at 1900 RPM

When the Reductant Fluid Quality Test is complete, the Reductant Fluid Quality Test Status parameter should display “Passed.”

Reductant Fluid Quality Test parameter “Passed” screen


4-12

Diesel Exhaust Fluid (continued)

Diesel Exhaust Fluid Quality Test NOTES: Perform Reductant Fluid Quality Test:

─ When incorrect reductant composition is monitored ─ When NOx catalyst efficiency reaches minimum threshold and DEF quality

warning displays When a DEF Quality Test is commanded resulting from DTC P20EE diagnosis,

disregard the first two test results. If the third test attempt fails, refer to Service Information for the proper diagnostic

procedure.

Repair Verification

Perform the repair verification procedures.

Road-test the vehicle to allow the ECM to perform and pass a self test.

Repair verification procedures will be different between DTCs. Refer to the specific procedure for the particular DTC that was set.

Warning

Road-test the vehicle under safe conditions and while obeying all traffic laws.

Do not attempt any maneuvers that could jeopardize vehicle control.

Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.

Post Repair Verification

Perform scan tool procedures:

NOx Catalyst Reductant Loading Reset

Diesel Particulate Filter Service Regeneration

Diesel Exhaust Fluid Quality Test


4-13

DEF Tester Scale


4-14

Module 4 Summary

Described DTC P20EE Diesel Exhaust Fluid System diagnosis ─ ECM and NOx sensors for controlling exhaust NOx levels

─ DEF certification requirements

─ Post DEF repair instructions

─ Repair verification procedure


MODULE 5 Incorrect Reductant Composition

6.6L Duramax: LGH and LML Diesel Engines Module 5: Incorrect Reductant Composition

5-2

Module 5 Objective

At the end of this module, you will be able to diagnose an Incorrect Reductant Composition concern on the 6.6L Duramax diesel engine.


Diagnostic Scenario

2011 GMC Savana Duramax Engine

Customer brought a 2011 GMC Savana into the dealership.

Diesel Exhaust Fluid (DEF) warning message EXHAUST FLUID QUALITY POOR displayed in Instrument Panel Cluster (IPC).

DEF warning indicator Preliminary Diagnosis:

Strategy Based Diagnosis (SBD) Diagnostic Information and Procedures Diagnostic System Check–Vehicle DTC P207F found set Diagnostic Trouble Code (DTC) List—Vehicle


5-3

DTC P207F

Service Information

For DTC P207F to set, the Engine Control Module (ECM) has determined that the incorrect reductant composition exists.


1. Ignition ON, observe the DTC information with a scan tool. Verify there are no DTCs set related to the following systems or components: • Diesel exhaust fluid system

• Engine misfire

• Exhaust gas recirculation

• Exhaust gas temperature sensors

• Fuel system - low or high pressure

• Indirect fuel injector

• Intake air flow valve

• MAF sensor

• NOx or HO2S sensors

• Turbocharger system


2. Test the diesel exhaust fluid for contamination. Refer to Contaminants-in-Diesel Exhaust Fluid Diagnosis.

If the diesel exhaust fluid is contaminated, replace the diesel exhaust fluid.

3. Command the Reductant System Leak Test ON with a scan tool. Allow the pressure to build for 30 seconds. Verify there are no leaks in the reductant lines.

4. Remove the Q61 emission reduction fluid injector from the exhaust pipe leaving the reductant line and electrical connector connected. Place the Q61 emission reduction fluid injector into a suitable container.

5. Ignition ON, command the Reductant System Leak Test ON with a scan tool. Allow the pressure to build for 30 seconds. The Q61 emission reduction fluid injector should not leak.

If a condition is found, replace the Q61 emission reduction fluid injector.


5-4

Video: P207F Diagnosis

Begin by removing the Diesel Exhaust

Fluid (DEF) injector from the exhaust pipe, leaving the electrical connector and the reductant line still attached.

If there is any build up of DEF or soot on the tip of the injector, clean it with a non-abrasive cloth, dampened with water.

Then place the injector in a suitable container.

With the Ignition ON, use the scan tool to command the Reductant System Leak test ON.

Allow the pressure to build for 30 seconds and then inspect the injector for leaks.

Electrical connector and reductant line—attached

Since there are no leaks, Service Information directs us to the emission Reduction Fluid Injector Quantity Test, which will require the following tools: ─ J 35616 GM-Approved Terminal Test Kit ─ J 39021 Fuel Injector Coil and Balance Tester ─ J 45873 Fuel Return Volume Test Kit

J 35616 GM Approved

Terminal Test Kit J 39021 Fuel Injector Coil and

Balance Tester J 45873 Fuel Return Volume

Test Kit


5-5

Video: P207F Diagnosis (continued)

Begin by inspecting the nozzle and cone area for restrictions that could affect DEF flow.

Disconnect the harness connector and attach the J 39021 Fuel Injector Coil and Balance tester to the injector using jumper wires and the correct test probes from the J 35616 Terminal Test Kit.

Disconnected harness connector with J39021 and jumper wires attached

Set the amperage supply selector switch on the J 39021 to the Coil Test 2.5 amp position.

Use the scan tool to command the Reductant System Leak test ON. Allow the pressure to build for 30 seconds.

Command the J 39021 ON and observe the injector spray pattern.

There should be 3 individual streams, and an atomization or mist of DEF should be observed. In our case everything looks normal.

Checking injector spray pattern


5-6

Video: P207F Diagnosis (continued)

The next step is to check the flow

volume of the DEF injector. For this we will need the graduated

cylinders from the J 45873 Fuel Return Volume test kit.

Position the DEF injector towards one of the graduated cylinders and command the Reductant System Leak Test ON with the scan tool, allowing the pressure to build for 30 seconds.

Checking DEF injector flow volume

Command the J 39021 ON four times, allowing sufficient time for the pressure to build up to at least 460 kPa (67 psi) between commands.

The DEF injector flow should be greater than 10 milliliters after four commands. In our case, the flow is below specifications.

Pressure at 560 kPa (67 psi) DEF flow below 10 mL specification

Note: If there is a build-up of DEF or soot on the tip of the injector, clean it with a non-abrasive clean towel or rag that has been dampened with water.


5-7

DTC P207F (continued)

Service Information

Repair Instructions

• Perform the following scan tool reset procedures after replacing the DEF or any other components not including the SCR/DPF:

1. NOx Catalyst Reductant Loading Reset

2. Perform the Diesel Particulate Filter (DPF) Service Regeneration

Note: The diesel exhaust fluid (DEF) must be greater than -7°C (19°F) and ambient air temperatures must be greater than -30°C (-22°F) before proceeding with this procedure.

3. Perform the Diesel Exhaust Fluid Quality Test. This test is necessary to reset the Reductant System history. Disregard the test results.

4. Perform a second quality test. If test fails, perform a third quality test. The test should pass.

If test fails, a condition with the system still exists.

• Perform the following scan tool reset procedures after replacing the SCR/DPF:

1. NOx Catalyst Reductant Loading Reset

2. NOx Catalyst Reset

3. DPF/Catalyst 2 Reset

4. Perform the Diesel Exhaust Fluid Quality Test. This test is necessary to reset the Reductant System history. If test fails, perform a second quality test. The test should pass.

If test fails, a condition with the system still exists.


5-8

DTC P207F (continued)

Repair Verification

1. Install any components or connectors that have been removed or replaced during diagnosis.

2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.

3. Clear the DTCs.

4. Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes.

Note: The diesel exhaust fluid (DEF) must be greater than -7°C (19°F) and ambient air temperatures must be greater than -30°C (-22°F) before proceeding with this procedure.

5. Ignition ON, command the Reductant System Leak Test ON with a scan tool. Allow the pressure to build for 30 seconds. Observe the scan tool Reductant Pressure sensor parameter. The reading should be between 425-575 kPa and there should be no leaks in the system.

Warning: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.

6. Engine idling at operating temperature. Accelerate at part throttle to 90 km/h (55 mph) with this speed maintained until the average SCR temperature is between 240-290°C (464-554°F).


5-9

Module 5 Summary

Diagnosed DTC P207F Incorrect Reductant Composition ─ Reductant System Leak test

─ Injector Quantity Test

─ Repair instructions

6.6l duramax: lgh and lml diesel engines 14, 2011 · 6.6l duramax: lgh and lml diesel engines how...

Documents