My Check Engine Light Adventure

[ixlr8a67]

Hope anybody can help me. As my screename indicates I am not very familiar with corollas, that being said here is my adventure with the "Check Engine" Light.

I have used a scanner I picked up at a local parts place to self diagose the light when it ist came on, and it indicated there was something wrong with the emissions system. Here is what I have replaced and the results.

I replaced both the Pre and Post converter Oxygen sensors = Light off of 10 mins.

I had the dealer replace the Air Flow Meter, due to error code P0171 System too Lean = Light off 1 week. I have taken the car back to the dealer and here is the latest, now the code is P0420 Cat Efficiency Below threshold Bank 1. They want $1400 to replace the cat converter. The car is a 2000 Corolla with 88,000+ miles and has always had regular oil changes and all the scheduled maintenance done at the dealer. My question is this: What are the realistic chances that replacing the cat will end my Check Engine light nightmare? And how can I tell if the Cat is going bad?

[Corolla2000]

I can't really speak to the specific problems you had, but I just thought I would let you know that I also have a 2000 Corolla and my check engine light went on yesterday. The dealership said that mine is the VS valve and they want about $213 for parts and labor. I realize it is a totally different problem than what you have, but it is another emissions system thing.

Anyway, I wanted to ask you where you bought the scanner to self diagnose it. I wish that I had done that because I paid $80 for the dealership to tell me what was wrong. How much did the machine cost? I know that my parents have figured out what is wrong with a few of our Dodge cars just by looking at some kind of codes on the cars themselves without any aid for a device.

[ixlr8a67]

I bought the scanner at a Kragen Auto parts here in Calif, about $100. Just plug into the diagostic port under the dash, and follow pretty basic instructions. Came with a manual to explain what the codes meant & I cross referenced with my Hayes Repair Manual. Hope it helps.

[ixlr8a67]

All parts have been replaced at the suggestion of the dealer. I just used the ODB-II to see for myself.

UPDATE:

The latest from the dealer was that the catalytic converter needed to be replaced because it was not properly absorbing the engine byproducts, can't remember the exact byproduct it was not consuming. Anyway the dealer wants like $1400 to replace the converter, after doing making some calls around town, I found a place that does nothing but Catalytic converters. They would replace the converter with a remanufactured one for about $300.

Since at this point I have little faith in the dealer, having now been asked to replace a 3rd part, for the same "Check Engine" light.

Would replacing with the remanufactured part by the way to go? Or am I asking for trouble down the road?

The urgency now is that the car needs to be smoked by the end of the month.