Catalytic Converter Failure

Maintenance/Repairs
1

I have a 1998 SL2 with 177k miles on it, and the dealer told me I have a failed catalytic converter, after I brought it in with a P0171 (engine too lean) SES code. I noticed no unusual behavior at all when I brought it in. I plan on getting a second opinion, but my quesetion is, why would a P0171 code be given for a failed cat? And if it is bad, can I drive it until my next vehicle inspection safely?

2

It’s not a matter of personal safety, it is environmental safety (pollution). You won’t damage your car, just the environment.

3

It’s not a matter of personal safety, it is environmental safety (pollution). You won’t damage your car, just the environment.

Well there is still that problem of the CEL staying on. mianghornes will not know if there is a new problem and that problem could cause damage or even be a safety issue.

Since mianghornes is going to need to correct the problem before his next inspection, I would suggest it would be better to do it now.
4

I smell dealer BS. The ECM uses other sensors to monitor the catalytic converter. These codes would trigger long before a P0171 if the cat were bad. A code P0420 would pop up if the catalytic converter were truly bad. Run away from these guys. The sensors that are detecting this condition are well before the catalytic converter, and the cat has no bearing on a lean running engine.

For the age of your car, I’d look for cracked, hardened, or broken vacuum lines. The engine too lean code usually pops up due to a vacuum leak letting in too much un-metered air, which leans out the fuel mix.

For the record, replacing broken vacuum lines is not a hard job, in fact is easy, and can be done very cheap. And certainly not as profitable as replacing a cat that doesn’t need it.

5

This question comes along frequently, about lean conditions, such as yours. You could read some of those posts if you went to Search at the top of this page, put in Keyword “lean engine”, or “P0171”. You’ll get a lot of good information, and, we don’t have to keep repeating ourselves. This lean condition is a problem with numerous makes of cars. Here is an example: http://community.cartalk.com/posts/list/2119905.page