Buick Firstland 3.0 check engine light on

Here I would like to share my experience repairing 2008 Buick Firstland 3.0 with you. The car, with LZC engine, was brought to my garage several days ago because of illuminating check engine light.

I started to diagnose its engine control unit after a rough glimpse, and retrieved an error code by using GM Tech2 diagnostic tool. According to the OBD2 tool, an engine misfire had occurred to the vehicle. Well, there are three possibilities of engine misfire: real misfire, fake misfire and fake-real misfire.

1. Real misfire

Real misfire often happens while the vehicle was idling or driving, with the dashboard light illuminating. Data from the car computer showed that the misfire occurred while idling. To determine if it was real misfire, I checked the ignition plug insulator. The ignition plug insulator was in good condition, which meant it was not real misfire. If you meet a real misfire, you can solve it by replacing a new ignition plug.

2. Fake misfire

Fake engine misfire is mainly caused by over-sensitive monitoring. The auto monitor program will set a false engine misfire because the vehicle ran too fast or too slow. Usually, the check engine light will not turn on when the car drove too slowly. I used GM Tech 2 to read data restored in the car computer and found the vehicle was driving at a speed more than 60km/h when the problem occurred. If it was fake misfire, the problem could be solved by refreshing the control program of the engine control unit. In this case, the problem was a fake misfire. I simply solved the problem after control program refreshing.

3. Fake-real misfire

Fake-real misfire means there are both fake misfire and real misfire. To deal with fake-real misfire, please refer to the two points above.