September 2010 Archives

Corroded or stripped electrical ground connections can cause a loss of module communication and other electrical system malfunctions, leading to unnecessary repairs and parts replacement. The electrical system relies on a secure, corrosion-free ground connection in order to function properly, so any damaged ground connections must be repaired to provide a good mounting point with a low resistance ground path and prevent future corrosion. 

During diagnosis of an electrical condition, which can have widely varying symptoms, test all control module grounds and system ground circuits. The control module may have multiple ground circuits. Other system components also may have separate grounds. 

Inspect the grounds for clean and tight connections at the grounding point. Also inspect the connections at the components and in splice packs, if applicable. Ensure that the circuit can carry the current necessary to operate the component. 

If it's determined that the ground connection is at fault, a recently released GM bulletin covering electrical ground connection repairs may help. Refer to GM bulletin #10-08-45-001 for ground connection repair and installation instructions. 

The bulletin outlines ground repair procedures using one of the following replacement fasteners with a conductive finish:

·       Welded M6 stud and nut (Fig. 4)

·       Welded M6 nut and bolt

·       Welded M8 nut and bolt

(Fig. 4)

Before installing a new fastener in the current ground location or at a new mounting location, remove any grease from the repair area using a residue-free solvent. 

After drilling the mounting hole (for a new location), remove any paint and primer from the area until bare metal is visible. 

Install the appropriate new fastener and check that it is securely fastened without any detectable movement. (Fig. 5)

(Fig. 5)

The M6 rivet stud will form a collar on the rear side to prevent rotation in the hole. (Fig. 6)

(Fig. 6)

Cover the stud threads with protective material and refinish the repair area using an anti-corrosion primer. 

The surrounding area must be properly finished prior to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 

Thoroughly clean the stud threads using a residue-free solvent. Once dry, apply dielectric lubricant to the threads to reduce the possibility of fretting. 

Fretting corrosion is a build-up of insulating, oxidized wear debris than can form when there is a small motion between electrical contacts, causing electrical resistance across the connection. 

Remove any corrosion or contamination on the electrical ground wire terminal. Install the terminal, tighten the conductive nut to the proper torque and verify system operation. 

Refer to the bulletin for a list of part numbers for the replacement fasteners and special tools.

- Thanks to Dave Peacy

One area of concern while removing and installing tire/wheel assemblies is corrosion on the mating surfaces of the wheel to the hub on the vehicle. Excessive corrosion, dirt, rust or debris built up on these surfaces can mimic a properly tightened wheel in the service stall. Once the vehicle is driven, the debris may loosen, resulting in clearance at the mating surface of the wheel and an under-torqued condition. 

Before installing a wheel, remove any buildup on the wheel mounting surface around the base of the studs and the hub and brake drum or brake disc mounting surface. 

If corrosion is found, remove the debris with a die grinder equipped with a fine sanding pad, wire brush or cleaning disc. Just remove enough material to assure a clean, smooth mating surface. (Fig. 7)

(Fig. 7)

Do not use use penetrating oils, grease or other lubricants on wheel studs to aid in removal or installation. Always use a suitable cleaner/solvent to remove these lubricants prior to installing the wheel and tire assemblies. Lubricants left on the wheel studs may cause improper readings of wheel nut torque. Always install wheels to clean, dry wheel studs ONLY. 

Beginning with 2011 model year vehicles, GM recommends putting a light coating of grease on the inner surface of the wheel pilot hole to prevent wheel seizure to the axle or bearing hub. Refer to Bulletin #06-03-10-010A for more information. 

Always inspect the wheel studs and lug nuts for signs of damage from cross-threading or abuse. Never force wheel nuts down the stud. Lug nuts that are damaged may not retain properly, yet give the impression of fully tightening. 

Always start wheel nuts by hand and be certain that all wheel nut threads have been engaged BEFORE tightening the nut.

If the vehicle has directional tread tires, verify the directional arrow on the outboard side of the tire is pointing in the direction of forward rotation. 

Improper wheel nut tightening can lead to brake pulsation and rotor damage. In order to avoid additional brake repairs, evenly tighten the wheel nuts to the proper torque specification as shown for each vehicle in the appropriate Service Information. Always observe the proper wheel nut tightening sequence in order to avoid trapping the wheel on the wheel stud threads or clamping the wheel slightly off center, resulting in vibration.

- Thanks to Mike DeSander

Two new Active Fuel Injector Tester (AFIT) adapters have been developed to connect to all current GM Spark Ignited Direct Injection (SIDI) engines (Fig. 8) and 2001-2010 Duramax Diesel engines.

(Fig. 8)

The AFIT adapter, called the Drive and Measurement Unit (DMU), is available for SIDI engines and diesel engines at a discount through the TSS program. Visit www.gmdesolutions.com/equipment and click Diagnostic Tools for more information. 

Adapter sets have been put together for service centers that repair mainly gasoline engines or diesel engines. Both SIDI adapter and diesel adapter sets are available separately, along with SIDI and diesel adapter cable sets. A shop that repairs mostly gasoline engines, for example, could purchase the SIDI adapter first and then purchase the diesel cable later to also have diesel coverage.

The AFIT/DMU can be used to diagnose essentially all fuel system-related conditions, but is especially useful for concerns such as crank, no-start; hard start; misfire codes; injector wiring codes; bank lean/rich codes; and power loss 

The AFIT can perform multiple fuel system tests, such as an injector coil test, fuel pump pressure leak-down test and injector balance test, without removing the injectors, helping to reduce diagnostic time. It uses a microprocessor and software program to completely automate testing procedures and eliminates variations in test results due to individual testing methods or changing fuel properties.

The Need for a New Adapter 

New SIDI engine technology represents a significant departure in the way fuel is controlled and injected into the cylinders of the engine. This technology has many benefits in improved performance, economy, and emissions. However, diagnosis of the system presents new challenges. Fuel pressures are much higher and the components are new and typically less accessible on SIDI systems compared to port injection engines. The new systems are dramatically different; technician familiarity and experience working on port injection systems does not apply to diagnosing SIDI systems except in a very general way. 

This tool automates the process and provides accurate, reliable information about all the elements of the fuel injection system. Current Service Information requires manual calculation and interpretation of the results to reach a diagnosis. The AFIT and DMU perform all the measurements and calculations automatically, giving an accurate diagnosis. 

The AFIT tool with the DMU Adapter tests all the components of the fuel injection system. From start to finish, testing, on average, takes less than 10 minutes. The test routine is completely prompted in the same way the AFIT tool does for port injection fuel systems. 

A number of diagnostic codes and many symptoms that do not set codes can be caused by a number of engine components. One of the values of the tool is to confirm the operation of the fuel system.

How the AFIT/DMU Works on SIDI Fuel Systems 

Using one of two mating cables, the DMU connects to the vehicle battery, the AFIT main unit, and to the vehicle ECM engine harness connector. (Fig. 9) The tester prompts the technician for the proper cable when the vehicle is selected on the AFIT main unit. 

(Fig. 9)

When prompted, the technician cranks the engine on the AFIT. The tool stops the cranking, and after each crank, one of the vehicle's injectors is tested. 

The fuel pumps (high and low pressure), starting system, and regulator also are tested for proper operation. When the test is complete, the results are displayed on the AFIT main unit in a format that is similar to the result screens for a port injection vehicle. 

SIDI systems use fuel pressures in excess of 1000 PSI provided by the engine-driven fuel pump. The fuel injectors are mounted so they inject fuel directly into the cylinders. Although they look different, they still rely on fuel pumps and regulators delivering the right pressures and injectors flowing the proper fuel amounts each cycle. 

While cranking the engine, the tool measures battery voltage and cranking RPM and compares those results to specifications for the vehicle. The tool determines high-pressure pump characteristics by measuring the fuel pressure developed at various engine speeds during each crank and comparing the results to the expected Pressure vs. RPM built into the tool's database. In addition, it verifies the low-pressure pump is delivering proper pressure to the high-pressure pump. 

The tool also performs a high-pressure leak-down test to determine if the system can maintain proper pressure and is not leaking. 

When all the injector tests are completed, the results are displayed on the AFIT main unit screen in both graphical and numeric form along with vehicle specific good/bad tolerances for the injectors. (Fig. 10) The results can also be uploaded to the AFIT Upload Utility installed on the shop PC.

(Fig. 10)

The tool can help technicians pinpoint the causal component in the fuel system that requires repair as well as eliminate the fuel system as the cause of a driveability condition.

- Thanks to Mike Cable and Tedd Magana

Every time a control module is programmed or replaced, there are different setup procedures to follow to ensure that the control module and related components operate properly. All of these setup and initialization procedures, as well as critical information to ensure proper programming, are covered in the appropriate Service Information for the vehicle being repaired. 

In GM Service Information, the Control Module References table (Fig. 11) includes links to all information related to the programming of a control module, including:

·       Control module/scan tool information

·       Schematics

·       Repair instructions

·       Programming and setup information

(Fig. 11)

Setup Procedures 

Once programming is completed successfully, it's critical to perform the necessary post-programming setup procedures. 

For example, when programming the Transfer Case Shift Control Module (TCCM), it's necessary to perform the Transfer Case High/Low Clutch Reset procedure. From the Control Module References table, there is a link to the setup procedures and the Transfer Case High/Low Clutch Reset procedure, which lists the steps to perform the reset procedure using a scan tool or the transfer case shift control switch. 

For some control modules, there may be only one opportunity to set up the module correctly. Be sure that all correct vehicle options are selected during module setup. Some options only appear during the initial module setup procedure. If the control module is setup incorrectly, it may be necessary to replace the module.

Proper Programming

To ensure proper programming, here are just a few of the items that should be checked before beginning the programming procedure:

·          Always verify a valid reason for reprogramming. For GM vehicles, available calibrations can be viewed online at tis2web.service.gm.com/tis2web. A control module should not be reprogrammed simply because there are updated calibrations available.

·          Nominal battery voltage should be 12.5 to 13.5 volts. This can be checked in most vehicles by connecting a scan tool and viewing the data display for the module. Look for the 'battery voltage' or 'ignition 1' signal to verify good voltage levels.

·          Due to the time requirements of programming a control module, connect an approved charger (such as the Midtronics PSC-550 or PSC-330) or a fully charged 12V jumper or booster pack disconnected from the AC power supply to maintain system voltage. Do not connect a standard battery charger.

·          The ignition switch must be in the On position, with the engine off. Do not change the position of the ignition switch during the programming procedure unless instructed to. Avoid programming interruptions of any kind, such as opening vehicle doors or depressing the brake pedal. It is also a good practice to make sure no other applications are active or running on the PC.

·          DTCs may set during programming. Clear DTCs after programming is complete.

If error codes appear during programming, do NOT assume that the control module cannot be programmed. There are certain events that can interrupt programming. In most cases, a second attempt at programming will be successful. For complete programming information, click the SPS link on the Control Module Reference table in the Service Information.

- Thanks to Bob Stewart and Mike Waszczenko

The TSS Q&A provides answers to common questions received by the ACDelco Customer Support Center.

Q:  What is the ACDelco Parts Points rebate promotion that is taking place this fall? 

A:  The ACDelco Parts Points rebate program runs September 1 - October 31, 2010 covering ACDelco OE service new alternators and starters (Line 31) and ACDelco remanufactured alternators and starters (Line 33). (Fig. 12) 

Points earned can be used to purchase gift certificates, merchandise and much more.

(Fig. 12)

Q:  How do I register my purchases for the rebate? 

A:  To register:

·       Go to http://www.acdelcorebatecentral.com (Fig. 13)

·       Select Trade Rebates (not consumer rebates)

·       Complete the required information, including your ACDelco TSS number

(Fig. 13)

Q:  Do I get a check in the mail with the points I earned? 

A:  You will receive points in an online account on www.ACDelcorebatecentral.com. These points can be redeemed for a number of items online, including gift cards.

You will be notified via email of your points. Once your rebate is finalized, an e-mail will be sent to the e-mail address on file with the details on your program points.

Q:  Why do I need to submit a rebate form instead of receiving this rebate automatically? 

A:  ACDelco is offering this promotion to service centers across the country to support their installation of specific ACDelco parts. By expanding the base of who can participate and to properly manage rebates, we require each participant to register and provide confirmation on their purchases. This opt-in ensures ACDelco accurately rewards their valued customers.

Q:  I am currently a TSS member and have an Exclusively Yours card, can I get EY points instead of rebate points? 

A:  TSS Exclusively Yours cardholders can transfer their promotion account points to their EY card.

Once your points are in your online account, you can transfer them to your regular EY card. There is no charge to transfer points. 

To transfer, log in to your account online:

·       Go to www.ACDelcorebatecentral.com

·       Redeem your points and select Transfer to EY card 

If you have any questions, please contact Rebate Headquarters at 1-866-870-6097.

Q:  I haven't received my ACDelco rebate from the previous promotion. Who do I contact? 

A:  Contact Rebate Headquarters at 1-866-870-6097 for the status of your rebate. 

If you have any questions about the TSS program or any current ACDelco activities, contact the Customer Support Center at 1-800-825-5886,
prompt #0.

Register by Sept. 30, 2010

Testing on Nov. 9, 16, and 18, 2010

Register online at www.ase.com

The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusual service repair, the TSS Technical Assistance Hot Line can help.
Call 1-800-825-5886, prompt #2, to speak with a technical expert with the latest OEM information. 

SIDI Fuel Line Service 

GM Ecotec 4-cylinder engine family (2007-2010 RPO LNF, 2009-2011 RPO LDK, 2010-2011 RPO LAF, and 2011 RPO LHU) and GM High Feature V6 engine family (2008-2011 RPO LLT, 2010-2011 RPO LF1, and 2011 RPO LFW), with a Spark Ignited Direct Injection (SIDI) fuel system 

When servicing a fuel line on a Spark Ignited Direct Injection (SIDI) fuel system on the Ecotec 4-cylinder engine family and High Feature V6 engine family, the fuel pipe must always be replaced when it incorporates a tube nut fitting. (Fig. 14)

(Fig. 14)

If a tube nut fitting is loosened for a fuel system repair, the line must be replaced because, after the tube nut is torqued the first time, the sealing surface on the ball end of the pipe becomes modified in a way that will not seal properly again. The ball end of the pipe is a softer material than the mating surface and, once pressure is applied from torquing the tube nut, it deforms to form a good seal. 

It can be determined that a fuel pipe has been previously installed by viewing the ball end of the pipe. After the tube nut fitting has been torqued once and re-installed, the sealing surface of the ball end will show dual sealing bands, indicating that the pipe has been previously installed. (Fig. 15)

(Fig. 15)

If a pipe has been removed only once, it will only show one sealing band. Because of the deformation that takes place on the first tightening, the material may not seal properly the second time, which is why the fuel pipe must be replaced. 

New fuel pipes are ready to use right out of the package. A blue or transparent dry lube may be noticed on the ball ends of the pipe. Do not wipe off this lube. It aids in achieving proper torque and sealing at the ball end fitting of the pipe. 

any time the fuel system is serviced, be sure to properly inspect, clean and torque the fuel pipe mating surfaces. Also, some fuel pipes have specific torque sequences that must be followed to ensure a good seal. 

Remote Keyless Entry Operation 

1997-2010 GM passenger cars and trucks 

To prevent battery drain, the Remote Keyless Entry (RKE) transmitter will lock up if any button or buttons are depressed longer than 30 seconds. The transmitter will unlock if another button is depressed. (Fig. 16)

(Fig. 16)

When unlocking the vehicle, if all doors are not unlocked after the second press of the unlock button, it may be due to the time delay needed by the system to recognize the second press of the unlock button. In order to unlock all doors, press the unlock button once, pause 1-2 seconds and press the unlock button the second time. There needs to be a pause between button presses so that the receiver can properly process the signal from the transmitter. 

For many 2006 and later GM models, the trunk release button requires a press and hold before the trunk lid will release. 

Squeak Noise on Brake Apply 

2004-2007 Buick Rainer; 2008 Buick Enclave; 2004-2010 Chevrolet Colorado, Chevrolet TrailBlazer models, GMC Canyon, GMC Envoy models; 2005-2009 Saab 9-7X; 2007-2008 GMC Acadia, Saturn OUTLOOK; 2008-2009 Chevrolet Malibu, Saturn AURA, Pontiac G6 

A squeak noise may be heard when the brake pedal is slowly applied with the engine on or off. It also may occur when the brake pedal is released. The noise may be isolated to the master cylinder area. 

To correct this condition, remove as much of the old brake fluid from the master cylinder as possible and refill with new DOT 3 brake fluid, P/N 88862806. Start the vehicle and fully cycle the brake pedal until the noise diminishes to allow the new fluid to enter the system.

Currently, over five million window regulators are replaced each year during service or collision repairs. To help meet demand in this growing market, ACDelco has introduced a new full line of all makes window regulators (Line 11) to complement the Original Equipment (OE) window regulators line (Line 18) for GM vehicles. (Fig. 17)

(Fig. 17)

The new line includes assemblies, motors, regulators and other parts and is designed and built to meet or exceed OE performance. It's backed by ACDelco's 12 month/12,000 mile warranty.

All-New Motors 

The window regulators feature all-new, not remanufactured, high torque motors. In addition to extensive testing for RPM, rotational direction, amperage and torque, the motors must pass: 

·          Durability testing that consists of thousands of up/down motions

·          Heat testing at 160 degrees

·          Cold testing at -20 degrees and water immersion tests where the motors must continue to run while frozen

·          Impact tests on hard surfaces

·          Testing of the unique self-locking safety design

·          Noise testing that ensures the motor does not exceed ACDelco's standard

·          Fit tests to ensure easy replacement

Easy Installation 

All of the ACDelco window regulators are exact fit components with the proper mounting holes, hardware and mounting brackets. 

All of the correct connectors also are provided, instead of several multi-use connectors, so there is no confusion or modifications necessary during installation. (Fig. 18)

(Fig. 18)

Smart Numbering System 

The window regulators line numbering system makes it easy to identify each part. 

11A1            "A" identifies an assembly (regulator and motor)

11R1            "R" identifies a regulator only

11M1            "M" identifies a motor only

11P1            "P" identifies the part as "parts" (gear set, lock actuator, switch)

Contact your local ACDelco distributor to learn more about ACDelco's new line of aftermarket window regulators and other quality door system components.

- Thanks to Kevin Smith

How to Take ACDelco Training 

Go to www.acdelcotechconnect.com and click the Training tab to log in to the ACDelco Learning Management System (LMS). 

·          To enroll in an Instructor-Led Training (ILT) course, click the Enrollment link or the Instructor-Led Courses link. 

·          To enroll in a Virtual Classroom Training (VCT) course, click the Enrollment link or the Virtual Classroom Training Courses link. 

·          To launch a Web-Based Training (WBT) course, click the Web-Based Courses link to view the catalog and select a specific course. 

·          To launch a TechAssist (TAS) course, click the TechAssists link to view the catalog and select a specific course. 

·          To launch a Simulation (SIM), click the Simulations link to view the catalog and select a diagnostic challenge simulation.

Training Schedule 

To search for currently scheduled courses, click the Schedule link. Select search terms from the dropdown menus and click the Submit button

Current Instructor-Led Training 

ACDelco's Instructor-Led Training (ILT) courses provide hands-on instruction on the latest automotive systems. Click the Schedule link on the LMS Menu to search the latest training schedule for courses held in your area. 

The following ILT courses are currently being held at training center locations around the country:

S-AC07-02.01ILT

Automotive Air Conditioning: Advanced Refrigerant System Diagnostics

S-AC07-03.01ILT

HVAC Control System Operation and Diagnostics

S-AC07-06.01ILT

Toyota HVAC

S-AC07-07.01ILT

Chrysler HVAC

S-BK05-01.01ILT

Braking Systems

S-EL06-04.02ILT

Network Communication Diagnosis

S-EL06-10.02ILT

Electrical Power Management

S-EL06-11.01ILT

Automotive Electrical Circuit Diagnosis and Repair

S-EL06-11.02ILT

Enhanced Automotive Circuit Diagnosis

S-EL06-12.01ILT

Hybrid Technology and Service

S-EL06-13.01ILT

Body Electrical: Global Diagnostics

S-EL06-14.01ILT

Advanced Body Control System Electrical Diagnostics

S-EP08-02.01ILT

Engine Performance: Computer Controls and Ignition System Diagnostics

S-EP08-03.01ILT

Engine Performance: Air Induction and Fuel System Diagnostics

S-EP08-04.01ILT

Engine Performance: Fault Monitoring and Emission System Diagnostics

S-EP08-05.01ILT

Engine Performance: Advanced Drivability Diagnostics

S-EP08-20.01ILT

Toyota Engine Performance

S-EP08-21.01ILT

Chrysler Engine Performance

S-EP08-81.01ILT

Duramax 6600: Diesel Engine Performance

S-EP08-81.02ILT

Duramax Diesel Operation and Diagnosis

S-SS04-01.01ILT

Vibration Correction Diagnostics

S-ST10-01.01ILT

Supplemental Restraint Systems