dgmattingley

I did a search but couldn't find anyone else reporting this exact problem. I have a CEL and the diagnotic shows 8 fault codes, 2 each for the 4 o2 sensors. Interested in best guesses as to what might be going on. Car is running fine, 56k miles on engine.

Stealth 993

Maybe check the plugs make sure there is not water or corrosion in them? I've never seen all o2's fail at the same time on any car.

Quadcammer

i had a similar issue...out of nowhere a bunch of 02 codes.

I reset the connection to the ecu, tightened every ground I could find, and reset (and cleaned with electrical cleaner) all the 02 plugs.

Problems gone.

Free and may solve your problem.

techman1

Any other trouble lights or electrical issues? A good start when more than 1 electrical gremlin pops up is the main ground strap at the battery. It may look brand new, but the strap and connection builds up resistance over time. Replaced mine and electrical gremlins disappeared.

dgmattingley

Plugs were all changed last winter, and old plugs showed normal wear.

Worth a try. By resetting the ECU connection, I assume you mean disconnecting the battery?

No other electrical issues, but the strap is worth a look I suppose.

Slow Guy

I think he means the plug into the ECU itself (under driver's seat IINM).

Give you an excuse to clean out all the $$$ hidden under the seat. I think I found $4 in change under there when I took my seats out to clean them.

Quadcammer

Well when you disconnect the ECU, its best to remove the negative battery cable at the same time, so you'll be doing both.

Essentially pull the computer off the floor, undo the connection, blow on the connectors old school nintendo style, and put it all back together.

Stealth 993

I wasn't talking spark plugs, but the o2 sensor connectors. Just removing them, cleaning off the connector then reattaching them.

dgmattingley

Thanks for the tip -- this worked, at least temporarily. Now the engine is out for a top-end so we'll see if it comes back in the spring.