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Anthony
Anthony, ASE Certified Technician
Category: Cadillac
Satisfied Customers: 11750
Experience:  ASE Master Automobile Technician with over 20 years exp. in this field.
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2006 cadilac DTS;Check engine light on

Customer Question

2006 cadilac DTS;Check engine light on
Submitted: 5 years ago.
Category: Cadillac
Expert:  Ron Z. replied 5 years ago.

When the Check Engine light comes on, it's the on-board computers way of telling you it sees a problem in one of the monitored systems. If you are not experiencing drivability issues (surging, stalling, rough idle, shifting issues, etc...), then more than likely it is a problem in the EVAP (emissions control) System. Unfortunately, there are litterally dozens of parts/sensors monitored by the PCM (on-board computer) in the EVAP System, and to take a "guess" would just be inefficient and a waste of time and money. A very common fail item is the Fuel Cap. Make sure it is tight and that the o-ring "gasket" on the underside is in good shape and free of visible defects (gaps, cracks, missing, etc). Fueling the vehicle while it is running can also set check engine light.. If the cap checks good, and you've done nothing out of the ordinary, then you need to start the disgnostic process. A good place to start is at your local parts store (ie. NAPA, AutoZone, Advanced). Most of these "big chain" stores will read the "p-codes" from the on-board computer for Free! Once you have these p-codes, it will tell you which system is faulting, and usually which sensor/part is the culprit (some testing is required), and then you can more accurately and efficiently make the repair.

Customer: replied 5 years ago.
Relist: Other.
car runs perfectlly;checked gas cap,no problem
Expert:  Ron Z. replied 5 years ago.
Like I say above- If you are not experiencing drivability issues (surging, stalling, rough idle, shifting issues, etc...), then more than likely it is a problem in the EVAP (emissions control) System. You will NEED to have the "p-codes" read to know "for sure" where the problem lies, as there are literally dozens of parts/sensors that are monitored by the PCM that can be faulty and show no signs of a problem beside the check engien light. There isn't a mechanic on the planet that can tell you "why" the light is on without retrieving the p-codes.
Customer: replied 5 years ago.
your answer did not help,that info is in the owners manual
Expert:  Anthony replied 5 years ago.

Hello Customer. Welcome to justanswer!

 

Different expert here....

 

Is there a parts store near you like Autozone?