p0171 leads to p0420??

[stefan2010_ca]

My 05 Corolla got hit by code P0171. Intake manifold gasket seal was corroded leading to rough idle on cold starts. I didnt repair this right away... waited a few months as summer was setting in...

Looks like this was a mistake as I have learned that the current code I have P0420 (catylitic converter below efficiency threshold) may have been caused by P0171.

Please take a look at the following youtube video and watch upto 1min15 sec.

You Tube

You Tube

Apparently there is a link between corroded intake manifold gaskets and failing Cats.

Please repair PO171 ASAP so your CAT doest not fail.

[Habs_Fan]

How long did you wait?? I might be having the same problem, I've had the p0171 code for over a week now, my rolla is idling super low (between 400-600rpm) but its not really rough, the car starts to vibrate a bit below 600rpm and the engine will struggle if it gets below 500rpm. I'm trying to determine if its the manifold gasket or something else.

[stefan2010_ca]

Habs Fan, I waited about 4 months as the problem was diagnosed in the spring just when the cold weather was going away. With no cold weather I didn't experience the rough idle, however upon reflection, putting off the repair was a dumb thing to do.

The gasket seal was still no good, so it didnt matter that I couldn't hear or feel the problem. It was still there and should've been fixed in a timely fashion.

Now I'm learning the catalytic converter failing is likely linked to my un-timely fix of p0171.

Habsfan, as Montreal is such a cold climate in the winter I strongly suggest you fix the problem ASAP. Have you scanned the posts for the Technical Service BUlletin toyota has issued to fix the repair plus step by step directions / suggestions by users? Type in P0171 into the search bar and you will find a wealth of information detailing the repair. If you know how to use a socket wrench and are able to stay organized you can do the repair in an hour. The part is $7. Please let me know if you need help. Dont be affraid to ask users. Let us know how you're doing with it... All the best. Go Habs Go.

[ryfly]

Yes, it does not take much to fail the cat.

Search my posts for a P0420 write up i did a month ago.