CONTENTS

New AFIT SIDI Kit Adapters & Software . . . 1

Data Bus Diagnostic Tool Update . . . . . . . . 1

Wiring Repair Strategy and the J-38125 Terminal Repair Kit . . . . . . . . . . . . 3

EBCM DTC Diagnostics . . . . . . . . . . . . . . . 3

Chattering Wiper Blades . . . . . . . . . . . . . . . 4

Driver-side Door Ajar Switch and DIC Message . . . . . . . . . . . . . . . . . . . . 4

Dimly Lit Service Engine Soon Lamp . . . . . . 4

HD Radio Operation . . . . . . . . . . . . . . . . . . 5

Customer Care and Aftersalescontinued on page 2

continued on page 2

Updates to the Active Fuel Injector Tester (AFIT) Spark Ignited Direct Injection (SIDI) Diagnostic Kit, essential special tool CH- 47976-500A, are currently being released to dealerships .

CH-47976-503 G3 Cable

One update includes a new cable (CH-47976-503 G3) and software for fuel system testing on the 2 .5L engine (RPO LCV) in the 2015 Colorado and Canyon . The cable plugs into the SIDI Drive & Measurement Unit (DMU) .

The pinouts for the ECM used with the 2 .5L engine in the Colorado and Canyon are different than the ECM used with the 2 .5L engine (RPO LCV) in the Cadillac ATS . The CH-47976-502A cable included in the previously released CH-47976-500A SIDI Diagnostic Kit will not test the 2 .5L engine in the Colorado and Canyon and will display an error on the AFIT .

Mid-April 2015, Volume 17, No. 8

New AFIT SIDI Kit Adapters & Software

Techline News

Data Bus Diagnostic Tool UpdateA software update to the Data Bus Diagnostic Tool application was released recently . The update includes screen shot functionality to help prevent accidental data loss .

Screen Shots

The application does not have a recording function, but it will save a screen shot any time data might be accidentally lost, such as when closing the application, changing tabs, or clicking the Clear button .

Users also can capture a screen shot at any time by clicking the Screen Shot button . These screen shots can be viewed by clicking the View Screenshots button in the Settings menu .

CH-47976-503 G3 Cable

2 Mid-April 2015

Techline News

New AFIT SIDI Kit Adapters and Software continued from page 1

Data Bus Diagnostic Tool Update continued from page 1

After 30 days, the screen shots will be automatically removed . To retain screen shots for longer than 30 days, the desired files should be moved to a different location .

Tool Applications

The Data Bus Diagnostic Tool helps identify a starting point in diag-nosing faults in a Controller Area Network (CAN) bus by looking at how connectors and wiring are working or not working . The software works with an MDI, a Techline terminal, and an active TIS license .

The application has three sub-applications:

Detected State – Identifies which control modules are responding to diagnostic requests and identifies the physical state of the vehicle bus being diagnosed

Measured Voltage – Provides a low speed voltage trace of the selected bus, CAN LO and CAN HI

Message Monitor – Passively monitors bus activity to help diagnose battery drain conditions

Download the Update

To download the latest software, click the GDS 2 icon on the TIS2Web home page .

Screen shot button

CH-47976-504 G2b Adapter

Another update includes a new adapter (CH-47976-504 G2b) and software for use with the AFIT on 2 .5L SIDI engines (RPO LKW) in the 2014-2015 Malibu and 2015 Impala with the engine stop/start feature . The new adapter plugs into the CH-47976-502A G2a cable and the three PCM engine harnesses for fuel injection system test-ing with the AFIT and SIDI DMU .

The adapter is required because stop/start has a secondary circuit that must be energized to crank the engine and build fuel pressure in the fuel rail for the AFIT SIDI tests . The CH-47976-504 adapter re-routes certain circuits so the CH-47976-502A G2a cable can be used .

Software Updates

Both AFIT updates include a new software download from the GM Dealer Equipment website . Only one software download is needed for both updates . Download the software through the Service Workbench selection of “Essential Tools – Software Updates” in GM GlobalConnect (U .S . only) . Open the file and follow the instruc-tions . It will take about 15 minutes to update the AFIT once the download is complete .

If you are experiencing difficulty or haven’t registered with GM Dealer Equipment, go directly to http://gmdesolutions .com/down-loads/ for software updates and additional information .

In Canada, the software is available through the Dealer Equip-ment Services (DES) Canada website . A link to this site is in the GlobalConnect library under Service/Tools and Processes and Equipment/Essential Tools – Software Updates .

If you need assistance, in the U .S ., call 1-800-GM-TOOLS (1-800-468-6657), select option #3, then select option #1, and then select option #2 .

Thanks to Chuck Berecz

CH-47976-504 G2b Adapter

If you have any questions about the application, contact the Techline Customer Support Center at 1-800-828-6860 (English) or 1-800-503-3222 (French) .

Thanks to Chris Henley

Mid-April 2015 3

GM’s global wiring repair strategy is to repair major harnesses (body, engine, instrument panel, forward lamp, etc .) whenever possible and to service minor harnesses (door, seat, steering column, etc .) as assemblies .

This direction was established to reduce the number of individual part numbers needed to service GM vehicles, as even small harnesses can have many different part numbers for the individual connec-tors and terminals . When new terminals or connectors are released within the major harnesses, they are serviced through the release of connectors, terminated leads, pigtails, etc ., and made available through GM Customer Care and Aftersales . If a terminal happens to be a legacy part already available in the J-38125 Termi-nal Repair Kit, it will be called out in the Service Information .

Additional information about GM’s wiring repair strategy can be found in the updated bulletin #13-00-89-008A .

Repair Parts

There are two sources for wire harness re-pair parts: the J-38125 Terminal Repair Kit and the dealership parts department .

The J-38125 Terminal Repair Kit is a very valuable resource . Many of the terminals that are available in the kit are still in use

on current model vehicles . The kit also con-tains many tools and instructions to service harness connectors and wiring .

TIP: Replenishment tools and terminals for the J-38125 kit are available through Bosch at 1-800-GM-TOOLS (1-800-468-6657) .

To download an electronic copy of the J-38125 Terminal Repair Kit Instruction Manual, go to the GM Center of Learning website at www .centerlearning .com . Click Resources > STC Training Materials > Service Technical Books . (In Canada, go to Library > Service > Technician Resources in GM GlobalConnect .)

Review the J-38125 Terminal Repair Kit Update Procedure on the TechLink Re-sources page to see how to organize and update the Terminal Repair Kit . This large file presents every step in the history of the kit .

New parts for major harnesses are released as terminated leads, connector kits and connectors . These parts are available only through Customer Care and Aftersales .

Parts Information

The Connector End View section of the Service Information is the source for part number information and where to obtain parts . The harness, connector and terminal part information is found just below the connector end view drawing .

TIP: Use TXL wire to maintain factory specifications for wire harness integrity . TXL wire is available through the Customer Care and Aftersales parts catalog within the Chemical Catalog section . In the Elec-tronic Parts Catalog (EPC), find TXL wire and fuses in the Chemicals – Fuses - Wire - book section .

Connector Repairs

Extensive repair procedures are covered in the Service Information . Go to Power and Signal Distribution > Wiring Systems and

Power Management > Diagnostic Informa-tion and Procedures .

The information covers wiring and terminal replacement procedures as well as disas-sembly instructions for various connectors . A listing of required materials to correctly perform wiring repairs also is provided, including splice sleeves and heat shrinking tubing .

On some 2014 Silverado 1500 and Sierra 1500 models and 2015 Silverado, Suburban, Tahoe, Sierra, Yukon and Yukon XL (excluding Denali) models equipped with the mid-level color Instrument Panel Cluster (RPO UDD) and a gas engine, the Service Engine Soon (SES) lamp may be dimly illuminated while the engine is run-ning . No DTCs will be set and the dimly illuminated lamp may be noticed only in dark conditions .

This condition affects vehicles built on or around August 1, 2014 – February 28, 2015

Replace the Instrument Panel Cluster using an exchange part ordered after March 20, 2015 .

Refer to #PIT5306, TAC Part Restriction – Instrument Panel Cluster, for ordering instructions .

Thanks to David Goodrow

Wiring Repair Strategy and the J-38125 Terminal Repair Kit

J-38125 Terminal Repair Kit

Connector End View part information

EBCM DTC DiagnosticsWhen diagnosing a current DTC C1100 SYM02 (Brake Booster Vacuum Sensor Circuit Short to Ground) set on a 2013-2015 Cruze and the diagnostic flow chart in the Service Information leads to replacement of the K17 Electronic Brake Control Module (EBCM), first monitor the Brake Pressure Sensor Data in the scan tool .

The 5 volt reference for the Brake Booster Vacuum Sensor Sup-ply is shared with the Brake Pressure Sensor that is internal to the Brake Pressure Modulator Valve (BPMV) .

If the voltage for the Brake Pressure Sensor data is reading constant (1 .08 volts without dynamic change; taken from a known vehicle), then it will be necessary to replace the EBCM/BPMV assembly .

Normal Brake Pressure Sensor voltage readings during service brake release and apply should range from 0 .5 volt to 3 .0 volts .

Thanks to Christopher Hightower

4 Mid-April 2015

Dimly Lit Service Engine Soon Lamp

Chattering Wiper Blades Driver-side Door Ajar Switch and DIC Message

The windshield wiper blades may chatter or skip across the windshield during operation on some 2015 Colorado and Canyon models built between October 1, 2014 and October 31, 2014 .

The wiper arm may be twisted in the incorrect direction, which affects the wiper blade angle and causes the wiper blade to bind during operation .

If this condition is found, replace the affected wiper arm .

Thanks to Charles Hensley

A Left Rear Door Ajar message may be displayed on the Driver Information Center and the dome lamps may not turn off when the doors are closed on some 2015 Express and Savana vans .

Inspect circuit 1179 for the driver-side 60/40 split door ajar switch being shorted to ground . The driver-side 60/40 split door option (RPO E26) is no longer offered but the door ajar switch wiring is still included in the body wiring harness .

Inspect BCM X6 connector terminal 15 for being shorted to ground . If circuit 1179 is shorted to ground, remove the termi-nal from the BCM connector and tape the circuit back into the harness since the circuit is not needed .

In addition, inspect the wiring around the driver’s front seat-belt retractor at the left B-pillar for any pinching to ensure no other wiring is damaged .

Thanks to Scott Fibranz

Service Engine Soon lamp on the mid-level color Instrument Panel Cluster

BCM X6 connector terminal 15

Incorrect wiper arm angle

Correct wiper arm angle

On some 2014 Silverado 1500 and Sierra 1500 models and 2015 Silverado, Suburban, Tahoe, Sierra, Yukon and Yukon XL (excluding Denali) models equipped with the mid-level color Instrument Panel Clus-ter (RPO UDD) and a gas engine, the Service Engine Soon (SES) lamp may be dimly illuminated while the engine is running . No DTCs will be set and the dimly illuminated lamp may be noticed only in dark conditions .

This condition affects vehicles built on or around August 1, 2014 – February 28, 2015

Replace the Instrument Panel Cluster using an exchange part ordered after March 20, 2015 .

Refer to #PIT5306, TAC Part Restriction – Instrument Panel Cluster, for ordering instructions .

Thanks to David Goodrow

Mid-April 2015 5

GM TechLink is published for all GM retail technicians and service consultants to provide timely information to help increase know-ledge about GM products and improve the performance of the service department .

Publisher:John Meade GM Customer Care and Aftersales

Editor:Lisa G. Scott GM Customer Care and Aftersales

Technical Editor:Mark Spencer /mspencer@gpstrategies .com

Production Manager:Marie Meredith

Graphic Design:5by5 Design LLC/dkelly@5by5dzign .com

FAX number: 3 1-248-729-4704

Write to: * TechLinkPO Box 500Troy, MI 48007-0500

GM TechLink on the Web: : GM GlobalConnect

General Motors service tips are intended for use by professional technicians, not a “do-it-yourselfer .” T hey are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle . Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely . If a condition is described, do not assume that the information applies to your vehicle or that your vehicle will have that condition . See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information .Inclusion in this publication is not necessarily an endorsement of the individual or the company .

Copyright © 2015 General Motors All rights reserved .

The AM or FM audio volume may change, mute, echo, cut in and out, repeat broadcast content, or skip intermittently on some 2013-2014 Enclave, Traverse, Acadia; 2013-2015 ATS, SRX, XTS; 2014 Regal, Captiva Sport, Corvette, Impala, Silverado 1500, Sierra 1500; 2014-2015 CTS Sedan (VIN A); 2015 Silverado HD, Tahoe, Suburban (without RPO AVF), Sierra HD, Yukon models (without RPO AVF), and Escalade models . The HD symbol on the radio display may turn on and off when these conditions occur .

These are normal operating conditions when listening to a weak AM or FM HD station .

Each station can have multiple HD stations . For example, if FM 93 .7 offers an HD signal, HD1 plays the same audio as the non-HD station and is shown as 93 .7 HD on the radio display . A station may have additional HD channels HD2–HD8, which may broadcast dif-ferent audio/songs . These channel presets would be indicated as 93 .7-2 through 93 .7-8, if available .

If the HD radio signal reception to channel HD1 is lost, the radio will revert to the main non-HD (analog) radio channel . The audio quality of the analog signal is not as crisp or clear as the HD signal . A weak HD signal may result in the radio switching back and forth between digital and analog signals .

If the HD radio signal loses reception to channels HD2–HD8, the radio does not revert to the non-HD version as it does when the HD signal drops out when listening to HD1 . Instead, the radio mutes until the signal can be recovered or until the channel is changed . Skips or echoes may be heard if the HD reception is weak . Digital HD broadcasting sig-nals are weaker than the normal signal strength of the analog station, so HD listening may not deliver the same range as non-HD stations .

HD Radio Setting

If signal reception is causing repeated cycling of the audio between analog and HD, HD may be turned off in the radio settings .

ATS, Corvette, CTS Sedan, Impala, Sierra, Silverado, SRX, Suburban, Tahoe, Yukon models and XTS:

From the home screen on the radio touch screen, select the Audio > Menu > HD Switching Off .

If the vehicle has a preset saved as an HD station, the HD will automatically turn on when that preset is pressed . It’s recommended to resave the presets as non-HD stations . Once the presets have been saved, the vehicle will need to power down for five minutes to correctly store the new presets .

Acadia, Captiva Sport, Enclave and Traverse:

From the home screen on the radio touch screen, select Now Playing > Menu > HD Disable .

If HD is turned off, selecting a HD preset will not turn HD back on . If HD is off and a HD2-8 station preset is pressed, a message will appear advising to turn on HD . Once the presets have been saved, the vehicle will need to power down for five minutes to correctly store the new presets .

Thanks to Ryan Dorland

HD Radio Operation

Select Menu on the Audio page to turn off HD.