Excessive carbon build up in the engine combustion chambers may be the cause of a smog check failure due to excess NOx emissions. A "top engine" decoarbonization cleaning procedure will commonly correct this concern.
Problems for specific Cadillac models:
Car problem reports
Problem with your car? See what our experts say or submit your own.
Most reported Cadillac problems
Illumination of the Check Engine Light may be the result of a loose or worn gas cap.
One or more fuel injectors may become stuck closed causing an engine misfire and the Check Engine Light to illuminate. Our technicians tell us that this problem can be caused by some fuel additives. There are special procedures which may be able to restore the affected injector. If this fails the affected injector must be replaced.
It is common for the fuel level sensor in the fuel tank read the fuel level incorrectly. The sensor must be replaced to correct the condition. Our technicians recommend having the complete fuel pump module replaced on high mileage vehicles.
The transmission may develop a harsh 1-2 shift and/or illumination of the Check Engine Light with code P1870 stored. This can be caused by wear of the bore for the TCC isolator and regulator valves in the valve body. This condition does not commonly occur until the transmission reaches normal operating temperature. If the valve body is worn, replacement will be necessary to correct this concern.
A burning smell may develop due to an oil leak form one or both valve cover gaskets. Resealing the valve cover will generally correct this concern. However, the valve covers should be inspected and replaced if damaged.
An engine vacuum leak may develop from the throttle body gasket causing a higher than normal idle speed. Failed gaskets should be replaced.
A common source of oil leaks is from the rubber transmission cooler lines. The fluid will often be red in color.