Car Problem Reports

Cadillac DeVille Smog Check Failure Due to Excessive Carbon Buildup

Cadillac DeVille Problem
7 Reports
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Model Years Affected: 1991, 1992, 1993, 1994, 1995

Average Mileage: 135,500 mi (113,000 mi - 158,000 mi)


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.

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