Archive for March 2015

The Stop/Start System and AutoStop Operation

If a vehicle does not engage in AutoStop mode or automatically restarts during an AutoStop event, some drivers may feel that the vehicle is not operating properly. Since AutoStop mode is based on many operating factors, it’s important to first verify that all conditions are met to enable AutoStop mode when presented with a stop/start system or AutoStop concern in the service department.

 

The engine stop/start system (RPO KL9) — the engine turns off when the brake is applied and the vehicle is at a complete stop under required conditions — is a standard feature on 2014-2015 Malibu and 2015 Impala (VIN 1) models equipped with the 2.5L engine (RPO LKW). The tachometer will read AUTO STOP during an AutoStop event. (Fig. 1)

 

F01 ss tach

Fig 1

 

TIP: Many of the conditions that allow, or shorten, an AutoStop event are not visible or controlled by the driver. In most cases, if an AutoStop event does not take place, it should be considered normal. If a system malfunction is the cause for loss of an AutoStop event, a DTC will be set.

 

When attempting to diagnose an AutoStop mode condition, review the Autostart Inhibit Reason and/or Autostop Disable Reason lists available in the ECM. The lists contain several parameters that are directly related to the Auto Stop/Start feature. They can be found in GDS 2 under ECM/Data Display.

 

The current state of several parameters that can inhibit a Stop/Start event are listed. The parameters can be viewed while operating the vehicle on the road or on a hoist with traction control turned off to assist in determining why an AutoStop event did not occur.

 

AutoStop Deactivation

 

AutoStop may be deactivated if:

• A minimum vehicle speed is not reached; minimum 12 mph (20 km/h) prior to the first AutoStop event, and then 6 mph (10 km/h) thereafter.

• The ambient, engine and transmission temperatures are not at the required operating ranges. Refer to the Stop/Start Enable Temperature Criteria chart.

• The shift lever is in any gear other than Drive.

• The battery charge is low; less than 12V.

• A/C compressor request from HVAC (A/C or defrost modes) – The interior comfort level has not been reached based on the climate control or defog setting. Use the ECO air conditioning mode (green indicator illuminated on the A/C button) for better efficiency (Fig. 2) and/or the humidity level is too high inside the passenger compartment, commanding the A/C compressor on within the Vehicle Personalization Settings.

 

F02 ss cc button r

Fig 2

 

• The AutoStop time is greater than two minutes.

• Hood switch status shows open. AutoStop will be disabled for the entire ignition cycle if the hood is open at the start of the ignition cycle.

• Brake pedal is not depressed beyond a specific value; approximately 27% for 2014 Malibu and approximately 24% for 2015 Impala and Malibu.

• Accelerator pedal is being applied.

• Brake booster vacuum is less than 45 kPa (7 psi)

• Engine speed is above 1,200 rpm.

• Battery state of charge in the ECM is less than 60%.

 

Screen Shot 2015-03-24 at 1.44.27 PM

 

More Information

 

A Web-based training course (16040.30W – 12V Stop/Start System) presenting an overview of the stop/start system is available at www.centerlearning.com (in Canada, go to www.gmprocanada.com).

 

Owner information on stop/start system operation can be found in the Getting to Know Your Vehicle guide and the owner manual.

 

– Thanks to Dallas Walton

 

Emailing and Importing GDS 2 Sessions

Technicians can email a stored data session from GDS 2 to GM representatives, such as Technical Assistance Center consultants or Techline Customer Service Center consultants, to help with diagnosis of a component or system. They also can receive a session and import it into GDS 2 to review it.

 

Email a Session

 

To send a session, follow these steps:

 

1. Click the Review Stored Data button. (Fig. 3)

 

F03 session 2

Fig 3

 

2. Click the Edit button below the listed sessions.

3. Click the checkbox next to the desired session to email. (Fig. 4)

4. Click the Email button. (Fig. 4)

 

F04 session 4

Fig 4

 

5. A window will pop up with the selected session attached along with the log files. Enter the email address. Additional attachments also can be added.

6. Click the Send button.

 

Import a Session

 

Perform the following steps to import and view a session:

 

1. When an emailed session is received, it will include a .zip file named Attachments.piz. (Fig. 5) Some email systems block .zip files so the file is renamed as a .piz file.

 

F05 session 6

Fig 5

 

2. Save the file to your PC.

3. Right-click the Attachments.piz file and rename it Attachments.zip. Double-click to open the Attachments.zip file.

4. Click the Sessions.piz file, and then click Unzip to a Selected Folder to save the files to your PC. (Fig. 6)

 

F06 session 10

Fig 6

 

5. Right-click the Sessions.piz file and rename it Sessions.zip.

6. Open GDS 2 and click the Review Stored Data button.

7. Click the Import Session button. (Fig. 7)

 

F07 session 12

Fig 7

 

8. Browse to the location where the Session.zip file is saved. Click the file and select Open.

9. The imported session will be listed in the Sessions section of GDS 2, at the top of the screen. Click the VIN and the stored data will display in the bottom section of the screen under Stored Data. (Fig. 8)

 

F08 session 14

Fig 8

 

As a reminder, GDS 2 automatically saves all VINs and diagnostic data for future viewing of stored data.

 

– Thanks to Chris Henley

 

Survey Results Drive TAC Enhancements

The GM Technical Assistance Center (TAC) in the U.S. is implementing a variety of improvements that will deliver an exceptional customer experience with every call. These changes are based on responses from the latest Dealer Service Survey.

 

The goal is to ensure that each TAC consultant provides superior service to every technician who calls. To ensure that TAC consultants, including Parts Quality Center consultants, are knowledgeable on the latest automotive technology and service concerns, they receive more than 1,000 hours of technical training each month.

 

TAC has put into action a standardized work project that streamlines all internal processes to ensure consultants are providing the most accurate guidance in the same manner when a dealership needs assistance. TAC also has implemented a Master Consultant Program, which provides immediate help for Tier 1 agents to deal with difficult cases.

 

In addition, to get the latest information to dealerships to repair vehicles quickly and accurately, TAC has published 214 PIs in the past three months for dealership technician use.

 

The success of TAC depends on a supportive relationship with dealership service departments. All of TAC’s enhancements are designed to provide an outstanding overall customer experience for GM owners.

 

– Thanks to Elizabeth Belland

Install Screen with New Condenser

When replacing the HVAC condenser on 2011-2012 Cruze models built prior to October 1, 2011 (excluding RPOs WA7 and BVG), a supplemental condenser screen should be installed to protect the condenser from stones or other foreign material/road debris. (Fig. 9)

 

2012 Chevrolet Cruze LTZ

Fig 9

 

If the condenser is inoperative due to frequent heavy stone or foreign material impact, poor air conditioning performance will occur, resulting in the following conditions: A/C will not blow cold air, A/C blows hot air or leaking refrigerant.

 

After replacing the condenser, install the condenser screen, part number 95927464. (Fig. 10)

 

F10 condenser screen

Fig 10

 

The screen snaps over the front of the condenser to prevent foreign materials that come through the front grille from causing possible damage to the new condenser. (Fig. 11)

 

F11 condenser

Fig 11

 

– Thanks to Steve Bruder

Remote Start Heated Seat Settings

On some 2015 Regal models, the heated seats may turn on during a remote start event even though the heated seat option has not been selected in the Vehicle Personalization Settings.

 

The current personalization menu option (Fig. 12) may show the following options:

• Off • On – Driver and Passenger • On – Driver

 

F12 4088957

Fig 12

 

However, the vehicle actually has an Off / On system for the heated seats during a remote start, which offers either both seats off or both seats on.

 

The correct personalization menu option is an Off or On selection only. (Fig. 13)

 

F13 4088958

Fig 13

 

An updated software calibration has been released to address this condition so that the correct menu will display. Reprogram the K9 Body Control Module (BCM) using SPS with the latest calibrations available on TIS2Web. For programming information, refer to the K9 Body Control Module Programming and Setup procedure in the appropriate Service Information.

 

– Thanks to Christopher Hightower

Normal Rear Window Defogger Clearance

On 2014-2015 Impalas, the rear window defogger does not clear the upper region of the rear window. This is normal operation for the rear window defogger. Do not make any repairs.

 

The upper gridlines on the rear window are radio antenna lines. They are not intended to heat when the defogger is activated. (Fig. 14)

 F14 4090089

Fig 14

 

TIP: Explain to owners the differences between the gridlines on the rear window to ensure they understand the proper operation of the rear window defogger.

 

– Thanks to Christopher Hightower

Front Seatback Cover Installation

The driver’s or front passenger’s seatback may lean or be turned outward (Fig. 15) on some 2014 Silverado 1500, Sierra 1500; 2015 Silverado, Suburban, Tahoe; 2015 Sierra, Yukon models; and 2015 Escalade models.

 

F15 4092446

Fig 15

 

This condition may be caused by the seat bottom trim cover not being installed correctly onto the cushion/foam. If the seat cover is not completely and squarely installed onto the cushion/foam (Fig. 16), it will give the appearance that the seatback is leaning or turned outward.

 

F16 4092450

Fig 16

 

Remove the seat bottom trim cover and reinstall it completely and squarely to the cushion/foam. (Fig. 17)

 

F17 4092453

Fig 17

 

– Thanks to Jim Will

Service Theft System Message

The Service Theft System message may be displayed on the Driver Information Center on some 2015 Colorado and Canyon models. DTC B2955 (Security Sensor Data Circuit) also may be set in the BCM.

 

Do not replace any parts for this condition. Inspect the connections at the immobilizer control module to ensure there is enough slack in the harness when the steering column is fully extended.

 

In addition, verify that there are not any proximity passes or fobs, except the GM Remote Keyless Entry transmitter, on the key ring. Any proximity passes or fobs should be removed.

 

If no issues are found and the DTC is set in history, notify the owner that GM is investigating the condition. Additional information will be released when it’s available.

 

– Thanks to Ken Cole

Vibration Analysis, Part 1: Tires

There have been several vibration conditions on 2014 Silverado 1500 and Sierra 1500 and 2015 Silverado, Tahoe, Suburban, Sierra, and Yukon models that have proved to be difficult to diagnose. These vibrations often occur at speeds of 35–45 mph (56–72 km/h) or 60–70 mph (96–120 km/h) and are felt in either the seat or steering wheel.

 

For example, one case from the Technical Assistance Center (TAC) was a concern about a vibration experienced at 70 mph and higher on a 2014 Silverado. At the dealership, after Road Force Balancing all tires, the Road Force Variation (RFV) measurements were: LF – 5 lbs., RF – 10 lbs., LR – 16 lbs., and RR – 20 lbs. In addition, the rear shocks were replaced.

 

A road test by a field service engineer using the CH-51450 Oscilloscope Diagnostic Kit with NVH showed a tire vibration amplitude of 22 mg at 70 mph. (Fig. 1) The tool’s sensor was placed on the seat track vertically.

 

F01 tire T2 22mg

Fig 1

 

Based on this information, the tires were moved from front to back on the same side. This put the highest RFV numbers on the front and the lowest on the rear of the vehicle. A second road test showed a greatly reduced tire vibration amplitude of 0.804 mg at 69 mph. (Fig. 2)

 

F02 tire T2 .804mg

Fig 2

 

Some of the vibration cases may be difficult — but with the right approach and the right tools, a successful diagnosis can be achieved quickly.

 

Diagnostic Information

 

A variety of helpful information is available in the Service Information.

 

Information on Vibration Analysis and Diagnostics – #PI1354B provides detailed information on vibration analysis and diagnosis for several different conditions. It outlines the recommendations and procedures for diagnosing and repairing vibrations caused by wheels and tires, axle components and propeller shafts. It also includes a vibration diagnostic worksheet to record vibration measurements.

 

Vibration Analysis Worksheet – Bulletin 03-00-91-001G is a vibration analysis worksheet that is to be used when road testing vehicles exhibiting vibration conditions. The worksheet lists the necessary data needed in conjunction with the appropropiate testing procedures in the Service Information.

 

Information Needed when Calling TAC – When calling TAC for diagnostic help on vibration conditions, there is some basic diagnostic information needed in order to provide proper direction in repairing a vehicle. Before calling, technicians should use #PIT5345 to understand what is needed on a vibration condition. The measurements listed in the PI should be gathered using the appropriate tools.

 

First Steps

 

The first step in determining the cause of a vibration is a test drive with the appropriate diagnostic equipment installed on the vehicle. If the correct tools are not used or the proper procedures are not followed, an incorrect diagnosis will result.

 

• Inspect the truck for any aftermarket equipment installations, such as non-factory tires, lift kits or running boards.

 

• Mark each tire valve stem location on the tire to check for tire slippage on the rim. After the road test, verify that the tires have not slipped on the rim.

 

• Use the CH-51450 Oscilloscope Diagnostic Kit with NVH for vibration diagnosis. The oscilloscope kit provides an accurate analysis of vehicle noise, vibration and harshness conditions and uses the display of your laptop computer to present clear, easy-to-read results and actions for repair.

 

• For seat vibrations, mount the oscilloscope kit sensor to the rear seat bracket. (Fig. 3, #1)

 

• For steering wheel vibrations, mount the oscilloscope kit sensor to the steering wheel bracket under the instrument panel. (Fig 3, #2)

 

• Moving the oscilloscope kit sensor from a vertical position to a horizontal position may indicate higher amplitude, which may be beneficial to help in diagnosis.

 

• Measure the vibration by driving the truck with the transmission in M5 to keep the vehicle from switching in and out of Active Fuel Management (AFM).

 

• Once the vibration readings have been recorded on a road test, verify the vibration data in the service bay. If using a hoist, the suspension must be at the same trim height as when the vehicle normally sits on the road.

 

F03 sensor position

Fig 3

 

TIP: If the vibration can be duplicated on the rack, the test should be performed a second time with the wheel and tire assemblies removed from the vehicle and the wheel nuts installed to retain the brake discs and/or brake drums. If the vibration is eliminated, focus on the wheel and tire assemblies as the source of the vibration. If the vibration is still present, focus on the vehicle driveline as the source of the vibration.

 

Another case example from TAC shows the importance of understanding how to use the right tools. The case was a vibration condition on a 2015 Tahoe felt at 40-50 mph and at 60-70 mph.

 

Four different tires, a rear driveshaft and a rear differential assembly had been installed to address the vibration condition.

 

After a road test, the field service engineer determined the primary vibration was a 2nd order tire disturbance.

 

Tire vibrations were measured with the CH-51450 Oscilloscope Diagnostic Kit. The initial RFV measurements for three tires were 25 lbs., 16 lbs., and 12 lbs. The fourth tire had a measurement of 8 lbs. (1st order disturbance), but also a 2nd order disturbance of 21 lbs. (Fig. 4)

 

F04 TIRE T2 21lbs

Fig 4

 

Reviewing the Hunter GSP9700 Road Force Balancer results for the tire with the 2nd order disturbance showed the 1st order harmonic was below specification, but the 2nd order specification was 21 lbs. (Fig. 5) It’s important to look at all harmonic measurements when reviewing the road force measurements and not to dismiss a particular tire based on only one measurement. If present, the CH-51450 Oscilloscope Diagnostic Kit tool will display the primary vibration as a 2nd order disturbance. Be sure to use this information and look at the other harmonic measurements on the Hunter GSP9700 Road Force Balancer.

 

F05 TIRE 2ND harmonic 21lbs

Fig 5

 

The vibration was corrected by replacing and match-mounting (or vectoring) all four tires. The RFV measurements were 1 lb., 4 lbs., 4 lbs., and 7 lbs. (Fig. 6)

 

#PI1354B lists a RFV specification of 15 lbs. for light truck tires. This specification is lower than the current specification listed in the Service Information. It should only be used if there is a speed-related tire disturbance. If the RFV of the tire is over the specification, match-mount (vector) the tire on the wheel. If that doesn’t bring down the measurement to within the specification, the tire should be replaced.

 

F06 TIRE T2 4lbs

Fig 6

 

TIP: When replacing tires, the road force should be checked before a test drive and after a test drive (minimum of 10–15 miles or 16–24 km/h). Road force on new tires will change dramatically after the tires are warmed up (as much as a 20-lb. reduction). After the test drive, the tire’s road force should be checked. If acceptable RFV cannot be achieved, first try vectoring the tire on the rim before an alternate tire is used. Refer to Bulletin #13-03-10-002: Diagnostic Tips for Difficult to Resolve Tire/Wheel Vibration Concerns.

 

– Thanks to Chuck Berecz, Dave MacGillis, Jeff Lobb, David Luka, Brad Harder, Michael Raposa and Reuben Gosewisch

 

 

Vibration Analysis, Part 2: Driveline

The sources of the vibration conditions that may be found on some 2014 Silverado 1500 and Sierra 1500 and 2015 Silverado, Tahoe, Suburban, Sierra, and Yukon models are most often the tires or driveline components, including axles and propeller shafts. These vibrations often occur at speeds of 35–45 mph (56–72 km/h) or 60–70 mph (96–120 km/h) and are felt in either the seat or steering wheel.

 

TIP: If the vibration can be duplicated on the rack, the test should be performed a second time with the wheel and tire assemblies removed from the vehicle and the wheel nuts installed to retain the brake discs and/or brake drums. If the vibration is eliminated, focus on the wheel and tire assemblies as the source of the vibration. If the vibration is still present, focus on the vehicle driveline as the source of the vibration.

 

Some vibrations may be difficult to diagnose even when the vibration can be duplicated. One example from a Technical Assistance Center (TAC) case was a concern about a vibration at 45 mph and higher on a 2014 Silverado 1500 4WD. The vibration was easily duplicated at these speeds. Initial diagnosis focused on a tire vibration.

 

A road test by a field service engineer using the CH-51450 Oscilloscope Diagnostic Kit with NVH showed a 1st order propshaft vibration with an amplitude of 7.83 mg at 49 mph. (Fig. 7)

 F07 Prop 1 783

Fig 7

 

The propshaft was balanced using the oscilloscope, but the condition did not improve.

 

TIP: For vehicles that are out of balance, perform a system balance. Using the two hose clamp method, the best driveline balance results are obtained under 10 g-cm. (Fig. 8)

 

F08 Prop 1 balance

Fig 8

 

Once the rear housing cover was removed, a 0.25–0.28 mm (0.010–0.011 in.) total variation of the backlash of the ring gear was found. The positions of the ring gear were swapped and side shims were installed to bring the backlash down to 0.1–0.12 mm (0.004–0.005 in.). However, the vibration was still present.

 

TIP: If the difference between all the measuring points is within specifications, the backlash at the minimum lash point measured should be 0.08–0.25 mm (0.003–0.010 in) with a preferred backlash of 0.13–0.18 mm (0.005–0.007 in).

 

The pinion and ring gear was replaced. A second road test showed a vibration amplitude of 0.722 mg at 45 mph. (Fig. 9)

 

F09 Prop 1 722

Fig 9

 

Available Training Courses

 

Tools alone cannot solve vibration conditions. There is not one root cause to many of the conditions and not one single approach to best address the conditions. This is why training is so important to properly address these conditions.

 

The GM Center of Learning has developed several training courses that incorporate the CH-51450 oscilloscope NVH kit for vibration diagnosis.

 

The following NVH training courses are available in the U.S.:

 

13042.14D1 – Noise, Vibration and Harshness (NVH) 1 (Virtual Classroom Training; 1.5 hour course): Covers components, characteristics and orders of vibrations. Two diagnostic scenarios are presented: one for a vibration in the seat, which includes performing a road test, and checking for excessive runout on tires and wheels, and a second scenario for a vibration in the steering wheel, which includes performing a road test, making tire calculations, using the road force balancer to measure road force variation and balance the tire and wheel assemblies.

 

13042.14D2 – Noise, Vibration and Harshness (NVH) 2 (Virtual Classroom Training; 2.0 hour course): Covers NVH diagnosis using the CH-51450 Oscilloscope Diagnostic Tool, reviewing operation, the oscilloscope software, and propshaft balancing using the tool. It also includes a diagnostic scenario of a vibration at 65 mph (105 km/h), performing a road test, vibration analysis – driveline, a service stall test, propeller shaft runout measurement, and driveline system balance adjustment; and a second diagnostic scenario covering difficult to isolate/balance component procedures and performing backlash measurement.

 

13042.14H – Noise, Vibration and Harshness (NVH) (Hands-On Training; 8.0 hour course): Reviews the basic principles of vibration diagnosis and correction and features exercise sessions in which participants work in pairs at workstations, including vibration analysis road tests. Participants will use the NVH Oscilloscope as well as the EVA tool to diagnose vibration concerns and use the Hunter 9700 Road Force Tire Balancer to properly balance a tire/wheel assembly.

 

13042.12W – Noise, Vibration and Harshness (NVH) (Web-Based Training; 2.0 hour course): Covers vibration theory and the operation of components that may cause abnormal noise or vibration concerns. It also covers diagnostic techniques such as road tests and test equipment used in diagnosing vibration concerns.

 

13042.13V – PicoScope Noise, Vibration, and Harshness Diagnostics Overview (Video On Demand; 15 minute course): Provides an introduction to NVH diagnostics with the CH-51450 Oscilloscope Diagnostic Kit, also known as the PicoScope. It covers the kit’s components and their functions as well as operating the tool to diagnose NVH and driveshaft imbalance concerns.

 

The following NVH training courses are available in Canada:

 

13042.12W – Noise, Vibration and Harshness (NVH) (Web-Based Training; 2.0 hour course): Covers vibration theory and the operation of components that may cause abnormal noise or vibration concerns. It also covers diagnostic techniques such as road tests and test equipment used in diagnosing vibration concerns.

 

13042.05D1 & D2 – Noise, Vibration and Harshness (NVH) 1 (Virtual Classroom Training; 1.5 hour each session): Session 1 of this two session course discusses three basic components of automotive vibration, vibration frequency, and orders of vibration. A diagnostic scenario is included which features the Electronic Vibration Analyzer (EVA) diagnostic tool. Various road and stationary tests are also discussed. Session 2 discusses two diagnostic scenarios and uses appropriate procedures in Service Information to diagnose concerns related to noise, vibration and harshness. The course also features information about the modes of operation for the (EVA diagnostic tool and its companion Vibrate software as well as procedures to perform vibration analysis.

 

13025.16H –Vibration Diagnosis (Hands-On Training; 8.0 hour course): Reviews how to diagnose and repair vibration concerns on passenger cars and light-duty trucks, covering vibration principles, i.e. terminology, vibration theory and a diagnostic approach. It also covers the use of the electronic vibration analyzing tool J-38792, and test result analysis. This is a practical hands-on program with on-vehicle work. Each student will participate in vehicle testing, diagnosis, and repair procedures.

 

Note: The VCT and Hands-On courses will be revised to relate to the CH-51450 oscilloscope NVH kit and its support in vibration diagnosis later this year.

 

13042.13V – PicoScope Noise, Vibration, and Harshness Diagnostics Overview (Video On Demand; 15 minute course): Provides an introduction to NVH diagnostics with the CH-51450 Oscilloscope Diagnostic Kit, also known as the PicoScope. It covers the kit’s components and their functions as well as operating the tool to diagnose NVH and driveshaft imbalance concerns.

 

Training and Tools

 

A recent TAC case on a 2013 Silverado 4WD illustrates the importance of proper training and the use of the correct tools during diagnosis.

 

In this case, after considerable time and multiple repairs, including a complete engine replacement, the vehicle was repurchased from the customer after the source of an engine idle vibration could not be found. The vehicle had a rough idle in gear during stops.

 

Using the CH-51450 Oscilloscope Diagnostic Kit with NVH showed a first order frequency with an amplitude of 5.66 mg at 525 RPM, which was significantly higher than a known good vehicle. (Fig. 10)

 

F10 engine 566

Fig 10

 

Once the baseline disturbance was measured, isolation of the first order engine disturbance and diagnosis could begin. Systematically, the serpentine belt was removed, and then the transmission torque converter was unbolted, which resulted in a first order engine frequency at an acceptable level. (Fig. 11)

 

F11 engine 126

Fig 11

 

The normal level of first order engine frequency was achieved by re-indexing the torque converter to the engine flywheel. No parts were required.

 

For more information about the available training courses covering vibration diagnosis, go to www.centerlearning.com (U.S.) or www.gmprocanada.com (Canada).

 

– Thanks to Chuck Berecz, Dave MacGillis, Jeff Lobb, Charles Mielke and Brad Harder

Hard to Close Rear Door

The rear door may be hard to close on some 2015 Colorado and Canyon extended cab models. The Rear Door Ajar message may be displayed on the Driver Information Center (DIC) and there may be a rattle noise from the lower rear door area.

 

These conditions may be caused by the rear door lower striker being out of position. First, verify which door is causing the conditions and also verify front door adjustment.

 

Next, loosen the two bolts on the lower rear striker and adjust the striker. (Fig. 12) Use care to protect the painted rocker panel. After adjustment, tighten the two bolts to 24 Y (18 lb.-ft.). Verify that the door properly closes fully.

 

F12 striker 1

Fig 12

 

– Thanks to Charles Hensley

 

Updated April 16, 2015

Intermittent Service Charging System Message/Battery MIL Illuminated

An intermittent Service Charging System message may be displayed on the Driver Information Center (DIC) and/or the battery Malfunction Indicator Lamp (MIL) may be illuminated on some 2014 Malibu models and 2015 Impala (VIN 1) and Malibu models.

 

2015 Impala and Malibu

 

2015 Impala and Malibu models equipped with the 2.5L L4 engine (RPO LKW) built prior to December 1, 2014 may have an illuminated battery MIL and DTCs P2096 (Post Catalyst Fuel Trim System Low) and/or P0621 (Generator L-Terminal Circuit) set as current or history DTCs.

 

If the Service Information diagnostic instructions for these DTCs does not lead to a root cause, update the ECM software. An updated software calibration has been released. Reprogram the K20 ECM using the Service Programming System (SPS) with the latest calibrations available on TIS2Web.

 

2014 Malibu

 

On some 2014 Malibu models equipped with the 2.5L L4 engine (RPO LKW, KL9), an intermittent Service Charging System message may be displayed on the DIC and/or the Battery MIL may be illuminated. This condition may be noticed during an Auto Stop event.

 

If the diagnostics for DTC P0621 (Generator L-Terminal Circuit) is performed according to the appropriate Service Information and no fault is found to be present or DTC P0621 is set in history, contact the GM Technical Assistance Center for further assistance.

 

– Thanks to Christopher Crumb

Appearance of Stowed Folding Top Side Rails

When lowering the folding top on 2011-2015 Camaro convertible models, the side rails, commonly referred to as the “deer legs,” may remain a bit higher than the stowage compartment. (Fig. 13) It may be necessary to push gently on the side rails to get them low enough to install the tonneau cover.

 

F13 4083123

Fig 13

 

This is a normal characteristic for these vehicles, especially for models with a new folding top. The movement of the side rails will improve over time as the material is cycled multiple times, but depending on many other factors (such as number of cycles and temperature) a slight protrusion of the side rails above the side of the body may be noticed.

 

The appearance of the side rails when the top is folded does not affect the quality or longevity of the folding top. Applying a slight amount of downward pressure to the rails will fully stow them.

 

– Thanks to Matt Bierlein

False DTC Set in HMI Module

On some 2014 LaCrosse models built on or before August 26th, 2013; and 2015 LaCrosse, Colorado (RPO IO4) and Canyon (RPO IO4) models, a false DTC B124B sym04 (USB 1 Circuit – Open) may be set in the Human Machine Interface (HMI) module.

 

Do not replace any components due to this code.

 

2014 Models

 

For 2014 models, reprogram the HMI module with the latest calibrations in TIS2Web, which were released on September 9, 2013, to address this condition.

 

2015 Models

 

For 2015 models, Engineering is currently working on new calibrations to correct this condition. Presently, ignore DTC B124B sym04 until the new calibrations are available.

 

TIP: This is not a USB programming event.

 

– Thanks to Ryan Dorland and Hassan Abdallah

Incorrect Song Information Displayed

When listening to a connected iPod® in some 2015 LaCrosse, Regal, ATS, CTS, SRX, XTS, Corvette, Impala, Silverado 1500, Sierra 1500; and 2015 1/2 model year Escalade models, Silverado HD, Suburban, Tahoe, Sierra HD, and Yukon Models (only Utilities and HD Pickup Trucks equipped with RPO AVF – Effective Point Control, 2015 1/2 M.Y.), the first song will still display when the next song in the list on the device is playing.

 

This condition can be remedied by pressing the Next button while the device is playing. (Fig. 14) This will enable the system to properly display the song information for the rest of the drive cycle. Engineering is currently looking into this condition and more information will be released when available.

 F14 next button

Fig 14

 

– Thanks to Dan Deline and Hassan Abdallah

Steering Wheel Rattle Sound

There may be a slight rattle, click or tick sound at the steering wheel area (Fig. 15) on some 2015 Colorado and Canyon models. Applying slight pressure, such as by resting your hand, on the center of the steering wheel may quiet the noise.

 

Do not replace any parts for this condition at this time. Engineering is investigating this condition. More information will be released when a repair is available.

 

F15 steering wheel

Fig 15

 

– Thanks to Charles Hensley

Service Know-How

10215.03D – Emerging Issues

March 12, 2014

 

To view Emerging Issues seminars:

• Log in to www.centerlearning.com

–   Select Resources > Service Know-How/TECHAssist > Emerging Issues > Searchable Streaming Video; or

–   Select Catalog to search for the course number, and then select View > Take or Continue Course

 

Service Technical College – New Training Courses

Following are the latest service technical courses available to technicians through the GM Service Technical College.

 

For more information about available service training courses, log in to the GM Center of Learning at www.centerlearning.com and click the Catalog link. Use the drop-down menus to search for courses by delivery type, audience, and category.

 

Screen Shot 2015-03-10 at 10.22.34 AM

Bulletin Review – February 2014

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