Archive for May 2017

SPS Updated to Prohibit or Warn about Programming with Same Calibration

In an effort to decrease the number of unneeded programming events, reduce the risk of programming-induced faults, and support timely vehicle repairs, the Service Programming System (SPS) has been updated recently to prohibit or warn users against programming a control module with the same calibration that is already present in the control module. This SPS change prohibiting reprogramming using the same calibration applies to all 2017-2018 Buick, Cadillac, Chevrolet and GMC models.


Prohibited Programming


On 2017 and newer models, reprogramming a control module with the same calibration that is already in the control module will be prohibited by SPS. Users who attempt to reprogram a control module with its current calibration will receive the warning message “You are attempting to reprogram with the same calibration. This is not allowed for the selected ECU.” (Fig. 1) Selecting OK will end the programming event.


Fig. 1


Warning on Same Calibration


On 2016 and older models, programming a control module with its current calibration is not prohibited, but is not a recommended service procedure. Users who attempt to reprogram a control module with the same calibration will receive a warning message. (Fig. 2)


Fig. 2


Selecting Cancel will stop the programming event. If OK is selected, a second warning will appear. (Fig. 3)


Reprogramming with the same calibration is not recommended, but selecting OK again on the second warning message will allow the programming event to proceed.


Fig. 3


These warning messages do not indicate an issue with the control module in question and that it should be replaced, only that the control module already has the calibration being programmed. Follow the diagnostic procedure in the appropriate Service Information to determine the root cause.


– Thanks to Andrew McKittrick


SPID Label Content Now Included with Certification Label

The Service Parts Identification (SPID) label, often located in the trunk or glovebox of a vehicle, lists a vehicle’s VIN, RPO codes and other information that identify the content of the vehicle. Beginning with the 2018 model year, much of this information will be available through a QR code on the Certification label (Fig. 1) on all Buick, Cadillac, Chevrolet and GMC models. The change will be phased in over the next several months.


Fig. 1


The two-dimensional QR code is a simple barcode that offers the former SPID information in a digital format. The Certification label on all GM models is located on the driver-side B pillar, with the exception of the Corvette where it’s on the driver’s door.


QR Code


Software to read the QR code is commonly available for any Android, iPhone or Windows smartphone. Many basic applications can be downloaded for free. Tested QR code readers that are easy to use include NeoReader by NM LLC, i-nigma by 3GVision, QR Scanner by Honestly App, QR Droid by DroidLa and Bar-Code by PW2. GM does not recommended any particular software.


Once the QR code is scanned, the vehicle information will appear in the following order: VIN, Model Year, Model, Build Month, Year, Engineering Book, Vehicle Order Number, 3 Digit RPO Codes sorted alphanumerically, and the Paint Code (same code appears in the lower left of the QR code).


For example, here’s the information as shown from a scanned QR code:


1GNKVGKD1HJ263691,2017,CV14526,03,16,17,TSNWHZ, AG5 AH5 AR9 AXP AYQ C67 DLT DS3 EF7 FE2 GZW IPC I17 JL9 LLT MAH M7X NP5 NT7 QD6 QLW TB4 UI2 UQF U2K V8D WMH X88 1LT 17U 5PK 6AB 7AB 8UM 83C 83I 9UM,636R, , , ,


The RPO codes are bolded above, but not in the actual information. The codes are separated by a space. Up to 48 RPO codes may be displayed. RPO descriptions can be found in the appropriate Service Information under General Information.


If the vehicle information needs to be retained for service records or shared with others, most scanner software also has a selection to email the data. (Fig. 2)


Fig. 2


– Thanks to Lisa Scott

Programming a Replacement OnStar Module

If the OnStar module is replaced in a 2009-2018 Buick, Cadillac, Chevrolet or GMC model, several conditions may occur if the module is not properly programmed or activated. These conditions may include a red LED illuminating, no Wi-Fi operation (Mobile Internet Connectivity RPO VV4 only) and limited OnStar module functionality occurring shortly after replacing the module.


TIP: Depending on model and model year, the OnStar module also may be identified in the Service Information, TIS2Web, the parts catalog, or a scan tool as the Vehicle Communication Interface Module (VCIM), Communication Interface Module, Telematics Communication Interface Control Module, or OnStar Vehicle Interface Unit (VIU).


Review every step of the Communication Interface Module Programming and Setup procedure in the appropriate Service Information to ensure all steps were completed.


If there is any question about the proper operation of the OnStar module, press the blue OnStar button to call OnStar. If OnStar confirms incomplete programming or activation, perform the Communication Interface Module Programming and Setup procedure again from the beginning without skipping any steps and then re-evaluate the concern.


Programming and Setup Tips


While all steps in the programming and setup procedure are important, the following items must be followed to ensure proper operation of the replacement OnStar module.


  • All replacement OnStar modules require TIS2Web programming. Complete every step of the Communication Interface Module Programming and Setup procedure.


  • U.S. dealerships should not select the TIS2Web selection that refers to Canadian upgrade bulletin #15-08-44-001 on a vehicle that has not had the Canadian upgrade performed. Programming and Service Activation should be selected. (Fig. 3)


Fig. 3


  • From the SPS Supported Controllers screen, select Programming and Service Activation. Do not select an incorrect option that does not apply to the vehicle (e.g. Export, Only for RPO XXX, etc.).


  • Select the Reprogram ECU option at the start of TIS2Web programming. Do not select the Replace and Reprogram ECU option. (Fig. 4)


Fig. 4


  • Do not select the OnStar Wi-Fi Enable (Gen 10 only) Programming procedure until the TIS2Web Programming and Service Activation procedure has been completed (RPO VV4 only). (Fig. 5)


Fig. 5


  • Press the blue OnStar button (Fig. 6) to call OnStar and confirm proper operation once the TIS2Web Programming and Service Activation procedure has been completed if required in the Communication Interface Module Programming and Setup procedure. To ensure that OnStar receives everything from TIS2Web needed to confirm proper operation, wait at least five minutes with the vehicle in an area with a clear view of the sky before pressing the blue OnStar button.


Fig. 6


– Thanks to Jamie Parkhurst



Mark of Excellence Q3 Test on Center of Learning

The Q3 (3rd quarter) Mark of Excellence Product Knowledge Test (U.S.) for technicians is available now on the Center of Learning website at Each of the four quarterly tests measure technicians’ knowledge of GM products. Questions are based on GM training, Service Information, Service bulletins and other resources.


Technicians who complete the Q3 test by July 28, 2017, with a score of 80% or better, will earn 50 bonus points towards their year-end recognition award. The Q1 and Q2 tests also can still be completed.


TIP: Tests are not part of a technician’s training path, but are listed separately under Mark of Excellence Product Knowledge Tests. The Q3 test can be found on the Center of Learning website under Course Catalog > Course Number Search: 30017.03P.


Technicians earn a quarterly drawing entry for successfully completing (80% or better) the Mark of Excellence Product Knowledge Tests. 10 technicians per zone will be selected by random drawing to receive 250 earnPOWER points.


In addition, technicians who successfully complete all four Product Knowledge Tests will receive an apparel item at year end.


Mark of Excellence Awards


The 2017 Mark of Excellence Program recognizes the top service technicians at GM dealerships for their achievements in technical training, product knowledge, customer satisfaction and outstanding years of service.


Awards available to technicians through the Mark of Excellence Program include:

  • Toolbox Medallion – complete a minimum of four Gold Level Certifications
  • 500 earnPOWER points – achieve one Master Certification and 65% dealer-level MPVI
  • Top Zone Ranking – potential to earn additional earnPOWER points as well as the opportunity for a technician and guest to attend a zone banquet (top 20 technicians per zone)
  • Top National Ranking – Top 50 technicians nationally earn the national travel award for a 3-day/2-night trip to Detroit to meet with GM representatives and visit the GM Heritage Center.


The 2016 national winners were recently recognized in the June edition of the Automotive News’ Fixed Ops Journal. (Fig. 7)


Fig. 7


– Thanks to Diana Sancya

Fuel Odor or Leak from Underhood Fuel Feed Pipes

A fuel odor or fuel leak in the front of the vehicle may be noticed on some 2016-2017 CTS, Camaro; 2015-2017 Escalade/ESV, Tahoe/Suburban, Yukon/XL, and Corvette models equipped with a V8 engine (RPOs LT1, LT4, L83, L86) and 2014 Silverado 1500 and Sierra 1500 models equipped with a V6 or V8 engine (RPOs LV1, LV3, L83, L86). A fuel leak may be found around the bellhousing or valve lifter oil manifold (VLOM).


In addition, the vehicle may be hard to start, have poor fuel economy, or a wet underhood foam insulator.


These conditions may be caused by a fuel leak at one of the high pressure fuel rail pipe connections that was incorrectly installed during service of another engine component that required the fuel system to be opened, such as fuel rails, fuel injectors, high pressure fuel pump, etc.


TIP: The engine fuel feed intermediate pipes must be replaced during any service repairs that require one or more of the pipes to be loosened or removed.


If any of these conditions are found, find the fuel leak by installing dye, P/N 88861206 (in Canada, P/N 88861259), into the fuel system via the fuel filler neck. Idle the engine for 15 minutes and then remove the intake manifold and inspect for leaks.


Tightening a nut is not an approved procedure. If a leak is found at any nut location, follow these procedures:

  • Leak in pipe 2 – change only pipe 2 (intermediate pipe 2)
  • Leak in pipe 1 – change pipe 1 and pipe 2 (intermediate pipe 1 and 2)
  • Leak in pipe 3 – change only pipe 3 (fuel feed pipe). (Fig. 8)


Fig. 8


Ensure that all interfaces are clean and free of debris before installing. After installing the new pipes, idle the engine for three minutes and recheck for leaks.


Replace the engine insulator if it absorbed fuel or emits a fuel odor.


– Thanks to Tracy Lucas

Proper Oil Filter Use on the 1.4L Engine

The 1.4L turbocharged engine (RPO LUV) available in 2013-2018 Encore, 2016 Cruze (VIN P), 2013-2015 Cruze, and 2013-2018 Sonic and Trax models uses two different oil filters. It’s important to correctly identify and use the correct oil filter for the engine.


Two different suppliers provide the oil filter housing assembly for the 1.4L engine. Each housing assembly requires a different oil filter. The correct oil filter must be used based on the oil filter housing assembly application.


Use the VIN to identify the correct vehicle in the electronic parts catalog (EPC). For part number and usage, see Filter Kit, Oil in Group 01.836 in the EPC.


TIP: Install a new oil filter cap seal ring (Fig. 9, C) at each oil change. Ensure the oil filter cap (Fig. 9, B) is completely seated on the oil filter housing assembly (Fig. 9, D) and the filter (Fig. 9, A) fits properly in the housing. If the cap is not completely seated, an oil leak may occur. Do not overtorque the oil filter cap.


Fig. 9


– Thanks to Jeff Kropp

Lack of Performance in High Ambient Temperatures

Some 2013-2017 GM models may have a lack of performance in excessively hot and sustained ambient temperatures over 100° F (37.7° C) due to vapor buildup in the fuel feed line. DTCs P2635 (Fuel Pump Flow Performance) and P018B (Fuel Pressure Sensor Performance) may be set.


If the vehicle has not had a fuel pump replaced, refer to #PIP5411 for additional diagnostic information. It may be necessary to replace the fuel tank fuel pump module assembly. (Fig. 10)


Fig. 10


If the vehicle has had a fuel pump replaced, advise owners to use fuels with an octane rating higher than 91 and to refrain from periods of extending idling, if possible.


– Thanks to Richard Renshaw

Service Know-How

10217.07V – Emerging Issues

July 13, 2017


The latest service topics from Brand Quality and Engineering are reviewed, including a closer look at the new 2018 Camaro ZL1 1LE (Fig. 11) and timing chain removal and installation on the 3.6L LGX engine.


Fig. 11


To view Emerging Issues seminars:

  • Log in to
  • Select Resources > Video on Demand > GM STC > Search Videos; or
  • Select Catalog to search for the course number, and then select View > Take or Continue Course

Cadillac CT6 PLUG-IN Delivers Efficient Performance

The new 2017 Cadillac CT6 PLUG-IN (Fig. 1) is a new type of hybrid vehicle that delivers added performance with an efficient powertrain. The turbocharged 2.0L 4-cylinder engine (RPO LTG) and hybrid electric variable transmission (RPO MRD) combine with a lithium-ion high-voltage battery to offer a hybrid powertrain capable of 31 miles (50 km) of electric range and a 0-60 mph (0-97 km/h) time of 5.2 seconds.


Fig. 1


EV Mode


The CT6 PLUG-IN works to provide the most efficient use of both propulsion power sources — the 2.0L turbocharged engine and the high voltage battery. (Fig. 2) When fully charged, the high voltage battery is the dominant propulsion power source and the engine will turn on occasionally to provide supplemental power.)


Fig. 2


The vehicle operates in EV mode under light or moderate driving conditions for approximately 31 miles (50 km) and up to speeds of 78 mph (126 km/h). Under aggressive acceleration, the engine will turn on to assist the high voltage battery. The engine will turn off and EV operation will resume once the vehicle is driven under light or moderate driving conditions again. The EV Operation Gauge on the instrument cluster indicates when the engine will turn on. (Fig. 3)


Fig. 3


When the high voltage battery is depleted, the engine is the dominant propulsion power source and the high voltage battery will provide only supplemental propulsion power. The Total Power Gauge shows the current source of power.


The high voltage battery will store enough energy to provide some hybrid/EV driving or supplemental power. Full EV driving can only resume if the vehicle is plugged in to charge. The Battery Gauge shows the high voltage battery state of charge. When the gauge reads empty, the vehicle should be plugged in to charge the high voltage battery and to allow maximum EV operation again.


Drive Motor Battery System


TIP: Technicians must be fully trained to service the CT6 PLUG-IN. This includes completing all hybrid training. Technicians also must follow all safety procedures and have Personal Protective Equipment (PPE) and up to date certified Class 0 HV Isolation Gloves.


The high voltage hybrid/EV battery is installed from beneath the vehicle, into the rear storage compartment. (Fig. 4) The battery energy control module, a current sensor, and the high voltage contactors are located within the hybrid battery assembly.


Fig. 4


The high voltage battery contains 192 individual lithium-ion cells. Every two cells are welded together in parallel for a total of 96 cell groups, which are electrically connected in series. The battery cell groups are joined to form three distinct sections. The battery sections also contain two temperature sensors. Diagnostics and system status are communicated from the battery energy control module to the hybrid powertrain control module 2 through serial data.


Other components (Fig. 5) of the Drive Motor Battery System include:

  1. S15 Manual Service Disconnect
  2. T18 Battery Charger
  3. K10 Coolant Heater Control Module
  4. K1 14V Power Module
  5. T6 Power Inverter Module
  6. G1 A/C Compressor
  7. C4B Hybrid/EV Battery Section 2
  8. C4C Hybrid/EV Battery Section 3
  9. A28 Hybrid/EV Battery Contactor Assembly
  10. C4A Hybrid/EV Battery Section 1
  11. K16 Battery Energy Control Module


Fig. 5


Parts Restrictions


The following components are on TAC Restriction to assist the dealership during diagnosis as well as to gather valuable feedback:

  • Drive Motor Battery (high voltage battery)
  • Hybrid Powertrain Control Module 2 (HPCM2)
  • 4EL70 Hybrid Transmission
  • CT6 Drive Motor Power Inverter Control Module (PIM)
  • Accessory Power Module (APM)
  • Drive Motor Battery Charger (OBCM) and Charge Receptacle


Cooling Systems


The CT6 PLUG-IN is equipped with three fully independent cooling systems.


The hybrid/EV electronics cooling system is dedicated to cooling the power electronics components — including the power inverter module, battery charger, and the power module — using the auxiliary radiator, engine control module inputs, radiator fans and hybrid/EV electronics coolant pump.


The high voltage battery is cooled and heated with pre-mixed DEX-COOL. Only use GM pre-mixed DEXCOOL, as it contains deionized water required for the high voltage battery and power electronics cooling systems. Use of any other coolant could result in potential Loss of Isolation DTCs.


A refrigerant/coolant heat exchanger (chiller) and the A/C compressor cools down the high voltage battery. A high voltage heater inside the high voltage battery can also heat the coolant entering the high voltage battery when needed.


The passenger compartment heater system uses the engine radiator, the auxiliary heater coolant pump, passenger compartment heater coolant control valve, high voltage coolant heater control module and a heater core to provide warm cabin air.


2.0L Turbocharged Engine


The 2.0L turbocharged 4-cylinder engine (Fig. 6) is designed for greater efficiency and power. The turbocharger generates up to 20 pounds (138 kPa) of boost and its twin-scroll design helps optimize the usable power from the engine. The engine produces 265 horsepower and 295 lb.-ft. of torque.


Fig. 6


Electric Variable Transmission


The new 4EL70 transmission (Fig. 7) is a fully automatic, rear wheel drive, electric variable transmission (EVT). It includes an input shaft, three stationary and two rotating friction clutch assemblies, a hydraulic pressurization and control system, an electric fluid pump, three planetary gear sets, and two electric drive motors. An external torque dampener, bolted to the engine crankshaft, is splined to the transmission input shaft.


Fig. 7


The hydraulic system includes a high pressure electric fluid pump driven by an electric motor supplied with high-voltage current from the power inverter module. The electric pump maintains working pressure and control of the clutches when the engine is on and when the engine is off.


The three planetary gear sets, electric motor-generators, and other clutches together provide all-electric propulsion, electric variable hybrid transmission ratios, and fixed mechanical transmission ratios. (Fig. 8)


Fig. 8




The Regen-on-Demand system enables the driver to control energy regeneration using the steering wheel paddles. Regenerative braking takes some of the energy from the slowing vehicle and turns it back into electrical energy, which is stored in the high voltage battery.


Regen on Demand allows the driver to increase the amount of deceleration provided by regenerative braking by pressing the paddles on the back of the steering wheel. It can be used during sporty driving and when descending hills to slow the vehicle. It also enables one-footed driving using the accelerator pedal and the selected deceleration level, which can be convenient in stop-and-go traffic. Select a deceleration level from M4 (fastest) to M1 (slowest) using the shift lever and the paddles to adjust the creep speed.


Information Displays


Several information displays are available on the infotainment system that provide an overview of hybrid operation. Select the Green Leaf Energy icon on the infotainment Home page and then touch the Flow, Charging, or Info icon. (Fig. 9)


Fig. 9


The Power Flow screen indicates the current system operating conditions, showing the power flow between the high voltage battery and engine through the transmission.


The Charging screens show the Charge Limit and Charge Mode status.


The Energy Info screens show the energy use (electric and gasoline) since the last time the high voltage battery was fully charged as well as how the energy was used.


High Voltage Battery Charging


The high voltage battery pack capacity is 18.4 kWh, but by design, only approximately 75% of the battery is usable to power the vehicle. The battery pack requires approximately 13–17 kWh to fully recharge, depending on temperature and battery condition. (Fig. 10)


Fig. 10


The minimum electrical circuit requirements for charging the vehicle are 120 volts/15 amps or 240 volts/20 amps. The charging times vary, but it will take approximately 4.5 hours to fully charge using a 240 V, 16 A charging station or approximately 20 hours using the default setting of 120 V, 8 A with the portable charge cord. (Fig. 11)


Fig. 11


The vehicle can be programmed for three charging modes: Immediately, Delay Charge Based on Departure Time, and Delay (Electric Rate and Departure Time).


Charging settings also can be saved for the vehicle’s home location. These settings will be used whenever the vehicle is parked at its home location. The settings can be changed in the Energy menu by selecting Settings on the infotainment system.


The charging indicator on top of the instrument panel (Fig. 12) shows the current state of the charging process.

  • Short Flashing Green Light – The vehicle is plugged in but the battery is not fully charged. The flash rate increases from one to four flashes as the battery charges.
  • Long Flashing Green Light – The vehicle is plugged in but the battery is not yet fully charged. Battery charging is in Delay Mode.
  • Solid Green Light – The vehicle is plugged in. The battery is fully charged.
  • Solid Yellow Light – The vehicle is plugged in but not charging.
  • No Light – The vehicle is not plugged in or there is an issue with the portable charge cord or the electrical outlet.


Fig. 12




To fill the fuel tank, press the fuel door button on the driver’s door. The Wait to Refuel message will display on the Driver Information Center. When the Ready to Refuel message is displayed, the fuel door will unlock. Press and release the rear edge of the fuel door to open it.


Special Tools


The following new tools were released for the CT6 PLUG-IN.


– Thanks to Sherman Dixon, Blake Streling and Keith Newbury

Using the Audio Diagnostic Tracks on a USB Drive

An audio system speaker malfunction may have several possible causes. One way to test speaker function is by using the audio diagnostic tracks on the EL-50334-6 Audio System Diagnostic CD or J-39916-CD Diagnostic CD.


Improper speaker mounting or loose trim, for example, may cause an audible buzz or distortion. During diagnosis, inspect the speaker and the surrounding interior trim for proper and secure mounting. Using the audio tracks on the audio diagnostic CD can help duplicate conditions and isolate components that react differently to various tones.


The audio tracks provide test tones for:

  • Bass/subwoofer test
  • Mid-range speaker tests
  • Door tweeter test
  • All speaker test
  • Speaker buzz and rattle test
  • Noise diagnosis


For use in vehicles that no longer have a CD player, the test tones on the CD can be copied to a USB drive or other device to use during testing. The test tones on the EL-50334-6 CD and J-39916-CD also can be downloaded from


Download Files


To download the audio files:

  1. Enter the tool number EL-50334-6 or J-39916-CD in the Search box on the home page of Click GO. (Fig. 13)


Fig. 13


  1. Click the CD image (Fig. 14) to display the Support tab.


Fig. 14


  1. Click the Support tab to view the available files. (Fig. 15)


Fig. 15


  1. To download individual audio files in a .MP4 format, right click on the desired video link and select “Save link as…” or “Save target as…”. To download all files in a .wma format, select the All Audio Files link.
  2. Choose the USB drive or folder location to save the file.


TIP: Audio files range in size; up to 5MB and are in a .MP4 or .wma format. Use a USB 2.0 drive to download the files. Check the Owner’s Manual to determine the correct format to use for the vehicle being repaired.


– Thanks to Chuck Berecz


Updated August 7, 2017

Installing Cruze Air Deflectors during PDI

The wheelhouse liner may be coming into contact with the tire on some 2016-2018 Cruze models. If this condition is found, verify that all four underbody tire air deflectors are properly installed in front of the front tires (Fig. 16) and rear tires. (Fig. 17) The deflectors are a structural part of the wheelhouse liner and damage may occur if the vehicle is operated without the deflectors or if the deflectors are not installed correctly.


Fig. 16


Fig. 17


The four air deflectors are shipped with the vehicle for installation during the Pre-Delivery Inspection (PDI). One air deflector should installed in front of each tire. There are different air deflectors for the front tires and rear tires. Make sure the underbody is clean before installing the deflectors. (Fig. 18)


Fig. 18


– Thanks to Bill Taylor


Updated July 10, 2017

Static Sound on Outbound Bluetooth Calls

On some 2017 Colorado and Canyon models equipped with the color radio (RPO IOB) with the 7-inch screen (Fig. 19), a buzz or static sound may be heard during the first 5-20 seconds of an outbound Bluetooth call. Only the person receiving the call, not the occupant of the vehicle, hears the sound.


Fig. 19


This example of the buzz sound demonstrates it may be similar to the noise of a foghorn.


In addition, the sound may occur only with the engine running, and may also be affected by placing the vehicle in gear.


If this condition is found, pair a phone to the vehicle, start the engine, and place a Bluetooth call to verify the person receiving the call hears the buzz sound during the first 5-20 seconds of the call.


If the sound is confirmed, command the generator off with GDS2 to determine if the sound is temporarily eliminated. If it is, do not replace any parts. GM Engineering is currently evaluating this condition.


– Thanks to Jamie Parkhurst

Duramax Diesel Hesitation and Other Conditions

Some 2017 Silverado and Sierra models equipped with the Duramax Diesel 6.6L V8 engine (RPO L5P) (Fig. 20) may have a hesitation, bump, harsh shifts or other related conditions. Any of the following DTCs may be set: P0097, P0128, P0181, P0263, P0266, P0269, P0272, P0275, P0278, P0281, P0284, P040C, P040D, P041C, P041D, P0483, P054F, P10D1, P11CC, P22FE, P24C7, P2635, P2636, or P2BAA.


Fig. 20


If these conditions are found, reprogram the Engine Control Module (ECM) and Transmission Control Module (TCM) with the latest calibrations available using the Service Programming System (SPS). Both the ECM and TCM must be updated to the latest software. Not updating both modules may result in additional undesired vehicle performance.


If the ECM and TCM have the latest calibrations, follow the diagnostic procedures for the set DTC in the appropriate Service Information.


– Thanks to John Stempnik

Misfire Conditions

A misfire condition may be present on some 2016-2017 ATS, CTS, Camaro; 2017 LaCrosse, Colorado, Canyon, Acadia, and XT5 models equipped with the 3.6L V6 engine (RPOs LGX, LGZ) and 2016-2017 CT6 models equipped with the 3.6L V6 engine (RPO LGX) or 3.0L V6 engine (RPO LGW). DTC P0300 (Engine Misfire Detected) or a DTC for a specific cylinder (P0301-P0306) may be set or stored in history.


If this is the first time the vehicle has had a misfire condition, there are several items to check, depending on the model.


2016-2017 All Gen 2 HFV6 Vehicles


If this is the first time DTC P0300, P0302 or P0305 is set in history, replace the Rocker Arm Oil Control Valve (OCV). After OCV replacement, command the oil pump to high pressure mode to ensure misfires do not return.


If misfires continue, review the misfire diagnostic information for the ignition and injection systems in the appropriate Service Information. If no cause is found, remove the cam cover on the affected cylinder bank and inspect for a rocker concern. To ensure that the rocker is working as designed, turn the engine over by hand and check that all rockers open. Replace and/or repair the rockers and lifters as needed.


2017 Lacrosse


If this is the first time DTC P0300 or P0304 is set in history on Cylinder 4 of the 3.6L V6 (Fig. 21), clear the DTCs and drive the vehicle in the same conditions the customer described to set the code originally. If the condition is verified, do not replace any parts at this time. GM Engineering is working on a repair.


Fig. 21


2017 XT5


If this is the first time DTC P0300 or P0306 is set in history on Cylinder 6 of the 3.6L V6, clear the DTCs and drive the vehicle under the same conditions the customer described to set the code originally. If conditions are unknown (this applies to XT5 models only), the misfire may occur by driving, from a cold start, one to three miles to a highway, and then applying heavy acceleration to merge into traffic.


If the condition is verified, do not replace any parts at this time. GM Engineering is currently evaluating this condition.


– Thanks to Aron Wilson

Malibu ECM Reprogramming

The Check Engine MIL may be illuminated and DTC P2097 (Post Catalyst Fuel Trim System High Limit) may be set on some 2016-2017 Malibus equipped with the 1.5L 4-cylinder turbocharged engine (RPO LFV). (Fig. 22)


Fig. 22


If this condition is found, reprogram the Engine Control Module (ECM) with the latest calibrations available using the Service Programming System (SPS). If the vehicle has the latest calibrations in the ECM, follow the diagnostic procedures for DTC P2097 in the appropriate Service Information.


– Thanks to Raymond Haglund

Service Know-How

10217.06V – Emerging Issues

June 8, 2017


The latest service topics from Brand Quality and Engineering are reviewed, including the prop shaft removal procedure on the 2017 LaCrosse (Fig. 23) and sound concerns on the Tremec 7-speed manual transmission on the 2017 Corvette Z06.


Fig. 23


To view Emerging Issues seminars:

  • Log in to
  • Select Resources > Video on Demand > GM STC > Search Videos; or
  • Select Catalog to search for the course number, and then select View > Take or Continue Course
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