Cadillac DeVille Problems

Check Engine Light on Due to Faulty Catalytic Conveter on Cadillac DeVille

Problem Description and Possible Solution

Failure of the catalytic converter can result in illumination of the Check Engine Light.

(51 people reported this problem)

Cadillac DeVille Vehicles With This Problem

RepairPal Fair Price Estimate
RepairPal Verified
Average mileage: 125,814 (65,000–220,000)
7 model years affected: 1991, 2000, 2001, 2002, more2003, 2004, 2005
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
Viewing 1-15 of 15 comments
code. used treatment with "seafoam" engine spray and lube $10 vs $300 after market converter or 1000 oem
Right after I bought the car the check engine light came on so I am not sure when it actually started. I bought it second hand. i have not fixed it.
Codes p0420 and p0300 are coming up. Replacing catalytic converter. There is only one right? The p0300 came up 2x on dash.
replaced catalytic converter a few days latter light came on again. replaced sensor, light came on again. mechanic said needs to be programed.
Check engine light came on and coded that it was an issue with the Catalytic Converter. Totally sucks.
Engine keeps getting hot also check engine light is on. Changed. Water pump radiator hoses cap gasket sealant flush. Don't know what else to do
I had light on CHECK ENGIN went to local Cadillac Dealer and was informed it was the CAT.Con. and I required a new one @ 3667.00 plus labour so I went to a well known muffler shop here in Kelowna,B.C. Canada and had a generic one installed for 350.00 inc. tax.labour and productand it runs just fine now / I was an un:suspecting buyer it had been a taxi in Culver city Ca. sold to a cab. in Nevada / and mills were rolled back to 50.000 miles/ I got all this info after I bought it from car fax ?? / I paid 7200.00 and spent about 3000.00 but it runs like a charm now / but get a used car checked befor you buy I never would have bought a used taxi/limo.
Just out of the 6 year / 100K certified warranty. It cost me over $1000.00 to repair. I was told this is because engine oil consumptiom burns them out.