error code on cat

96 Silverado 2WD 5 spd 305 125K miles

Well, after two tanks of gas and really making sure the gas cap was tight I had the error code pulled and it was my catalytic converter :(

Autozone pulls the codes for free, so I had him clear it and I am waiting to see if it comes back.

How does the computer know the cat is bad? Autozone could not get a price as it was in the evening and dealers were closed. Is the cat a dealer only item?

Thanx Mike

Reply to
Mike Copeland
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The computer "sees" catalyst efficiency via the post-cat 02 sensor.

99.9% of the time it's the sensor that's FUBAR, NOT the cat itself.

Get the EXACT code that was pulled and I'll tell ya which sensor it is.

Doc

Reply to
"Doc"

Thanx Doc, if it comes back I will get the exact code. But, I was not aware there were any sensors downstream of the O2 sensors. I thought everything after the cat was just "bolt-on" stuff that could easily be replaced without needing to play with sensors or affecting the computer. Guess I need to poke around under there some more. Mike

Reply to
Mike Copeland

====== ======

The computer "sees" catalyst efficiency via the post-cat 02 sensor.

99.9% of the time it's the sensor that's FUBAR, NOT the cat itself.

Get the EXACT code that was pulled and I'll tell ya which sensor it is.

Doc ========= =========

What Doc said. ditto

as a side note..... a muffler shop will test the cats for free.

MarshMonster ~:~ =============== ===============

Reply to
Marsh Monster

There are 1 or 2 post catalytic 02 sensors.

Doc

Reply to
"Doc"

Been driving it for a few days now and CE light has not come back on. Thanx Doc and Marsh. If the light comes back I will get the exact codes and revive this thread. Mike

Reply to
Mike Copeland

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