The dealer will normally check the CAT by doing a backpressure test, where they remove one of the O2 sensors and install a fitting to a gauge to test for excessive backpressure.
If CAT is not bad, you are under no obligation to have them replace the O2 sensors, just tell them you want a backpressure test performed, get results and go from there. You will, of course, have to pay for test.
OR, remove CAT yourself (it's bolted on) and inspect for black soot, melting, cracking.
Handle CAT carefully, DO NOT DROP IT.
Friday, April 24th, 2009 AT 10:55 AM