Car Problem Reports

Cadillac Seville STS Smog Check Failure Due to Excessive Carbon Buildup

Cadillac Seville STS Problem
2 Reports
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Model Years Affected: 1991, 1992


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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