General Motors (GM) Archives - Page 4 of 4 - UnderhoodService
State-Of-Charge And Charging Systems Diagnostics On Late-Model GM Vehicles

On 2007 and up GM vehicles, using conventional battery and charging systems tests can prove inconclusive. This is because of GM’s Electrical Power Management (EPM) system designed to monitor and control the charging systems and send diagnostic messages to alert the driver of possible problems. The EPM system primarily utilizes existing on-board computer capabilities to maximize the effectiveness of the charging systems, manage the load, improve battery state-of-charge and life, and minimize the system’s impact on fuel economy.

Diagnostic Dilemmas: Pinball Effect: Sorting Through Multiple Codes and Problems

“My dash lights up like a ­pinball machine, the ­engine loses power for a few seconds, and then seems to run OK.” Although I’d actually been chasing this Diagnostic Dilemma for the better part of a year, this four-wheel drive 2001 Blazer equipped with the 4.3L Vortec engine and manual transmission otherwise appeared to be

GM: Eliminating Air Conditioning Odor

Models: 2014 and prior GM passenger cars and trucks Some customers may comment about musty odors emitted from the HVAC system at startup in hot, humid conditions. Cause This condition may be caused by condensate buildup on the evaporator core, which doesn’t evaporate by itself in high humidity conditions. The odor may be the result

GM Air Conditioning odor
Must-Read TPMS Technical Service Bulletins

Here’s a rundown of the top technical service bulletins related to TPMS. These TSBs should be analyzed by every technician that services TPMS. Audi TSB Number: 4413382034445/1 Models: 2010-’14 A4/S4, A5/S5 and Q5 Summary: This TSB addresses TPMS MIL lights that are not related to a loss of pressure. The TPMS light may illuminate if

Legendary Spark Plugs: The Six Toughest Vintage Spark Plug Replacements

1. AMC Pacer: The Pacer was supposed to get a GM Wankel rotary engine. If this were the case, the four plugs would have been easy to access. But thanks to emissions problems, the Pacer would get the regular AMC straight six. This forced the engineers to put plugs 5 and 6 under the windshield.

Chevrolet: Navigation Information Not Displaying Accurate Location

Customers may complain the navigation radio is not displaying the correct vehicle location icon on the map accurately after a radio or battery has been replaced or after battery power has been removed from the radio. The vehicle location icon accuracy may be degraded if the GPS signal is not available and the GPS displayed

Everything You Need To Know About Stretch Belts

Stretching the belt may seem counter intuitive after everything you have been told about serpentine belts. But stretching the belt with the right tools is often the only way stretch belts can be installed. Stretch belts can take loads off of the main accessory belt drive, allow for better packaging and solve NVH problems that

2014 4.3L V-6 EcoTec3 AFM VVT DI (LV3) for Chevrolet Silverado and GMC Sierra