2001 Pontiac Bonneville P0420

• Comments ⇓

2002 Pontiac GP codes = P0420.
Repairs done prior = REPLACE CAT. DUE TO MELT DONE AT 90K, REPLACED UPPER INTAKE BECAUSE OF COOLANT CONTAMINATION. AT 102K, ALSO BOTH O2S, REPLACED WITH CARDONE AFTER MARKET CAT HAS HAD THREE INSTALLED CODE COMES BACK AFTER 3- 6 MONTHS OF DRIVING, TECH INSISTED GM CAT WILL FIX, I'M NOT SURE HELP, DO NOT WANT TO GUESS!!

Repair for this problem:
AFTER MARKET catalytic converter, 3 TIMES. UPPER INTAKE gaskets REVISION, TUNE-UP WITH spark plugs AND WIRES AND FUEL FILTER.

Question:
I'M TOLD THAT THE GM CAT WILL FIX THIS I'M NOT CONVINCED, CODE PO420 EACH TIME TECH INSISTS THAT IT WILL FIX IT. SAID AFTER MARKET CATS. Was BAD SUPPLIER.

ANSWER:

Yes, i have seen this a few times where an inexpensive after market catalytic converter fails. Some just don't clean the exhaust good enough for the computer. Be sure to have the fuel pressure regulator checked for leakage. A leaking regulator will cause a rich condition, and can contribute to a converter going bad. With a GM converter, this would have to be leaking very badly, and you would normally see other driveability symptoms before the converter failed. You may be in luck.

There is what is called a "Special policy adjustment" for failed converter on your car that may apply. It is kind of like a recall, but you may not get a letter in the mail. GM will replace failed converter for up to 10 years, or 120,000 miles under warranty. The problem is that you have an after market installed already. You may be able to get the new GM part under warranty by going to a dealer with the original receipt from the first replaced converter.