2001 Cadillac DeVille Q&A
2001 Cadillac DeVille Question: check engine light is on
When I press my brake the car shimmeys and when I slowed down to 30 25 mph it started lightly jerking. Than it went away. I drove today at 55mph and it started to jerk again. My check engine light has been on for this past week, I got it checked at a local mechanic he hooked it up to a machine but couldn't find anything wrong. What's going on with my car. He turned the check engine light off twice but it came on again when taking the car for a test drive. Help! - ericaizzyb
If the check engine light is on, there is a code stored in the engine control module, and the "mechanic" seems to be erasing the code to turn the light off but not diagnosing what is wrong. Can you post the diagnostic codes that the mechanic pulled from the control module? - Bret Bodas
engine light on. 20miles tothe gal. car works great. took to dealer 1860 now I have a bill of 3300.00?????????????. - Visitor
Failure of the catalytic converter can result in illumination of the Check Engine Light.
Two likely causes for the Check Engine Light to illuminate would be a loose or worn gas cap or a faulty catalytic converter.
An intake manifold vacuum leak can develop from a variety of sources, often causing illumination of the Check Engine Light with codes P0171 & P0174 stored. Thorough diagnoses will be necessary...
The EGR control solenoid or EGR valve may fail causing the Check Engine Light to illuminate.
Illumination of the Check Engine Light can be caused by a loose or worn gas cap.