Close
Cadillac DeVille Problems

Smog Check Failure Due to Excessive Carbon Buildup on Cadillac DeVille

Problem Description and Possible Solution

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.

(8 people reported this problem)

Cadillac DeVille Vehicles With This Problem

RepairPal Verified
Average mileage: 135,500 (113,000–158,000)
5 model years affected: 1991, 1992, 1993, 1994, more1995
Not Your Cadillac DeVille Problem?
Brake problem? Or maybe a faulty head gasket cylinder?
Learn About Your Car Problems
Search For a Specific Car Problem