P0141 still being set

compatible?

problem?

site:

part:

Prizm):

Maybe email your VIN # and other pertinent details to the local Geo/ Chevy dealer? I would imagine they could reference a part # and/or cross reference...

There will be a part number on the ECU, and any replacement ECU should have an exact match. I do not know if an ECU for a Corolla is compatible with the one for a Prism, so I would stick with one for a Prism. As MrStevo suggested, your local Chevy/Geo dealer may be able to provide a part number and cost for a new one so you have a reference to go buy when shopping for a used one.

I actually called them and asked them what the cost for a new one is and they said that it is $495, so I would prefer to be able to find a used one. But I'll give them another call and see if they can give me the part number. Thanks, Dave

compatible?

problem?

site:

part:

Prizm):

I was able to get the part number from the Chevy dealer by giving them the last 8 digits of my VIN, so that worked out great.

Also, the owner of one of the eBay sites recommended that I check out this website:

Make sure the wire harness doesn't have any extraneous grounding wires or cuts in the insulation before you install the replacement ECU.

good luck!

Speaking of, I found an ECU out of boredom on eBay that appears to match specs / part #'s with my current one. They only wanted $5.00 + $20 shipping. I figured I would buy it since it was cheap. Doubt I would ever need it.

Anyway, they claim it should be fine and such. Seems a little odd it was so cheap.

So, since I have never seen one... are they easy to hook up to an electrical source? I'd love to hook one up and get some software and the stuff for my laptop and actually play with one... that I can't harm.

Or if that's too much hassle -- perhaps just save it in case I ever happen to need it.

The ECU is silver, about the size of an external CD player, and about an inch and a half thick.

They are not that easy to hook up to an electrical source since the connector is not something you come across at Radio Shack.

If you are going to store it, put it in a zip lock bag along with some desiccant bags and store it in a cool dry place.

OK, so I finally got around to replacing the ECU with the new one and it still comes up with code P0141. I guess that it's possible, but I doubt that both of the ECUs have the exact same problem to bring up the same code, so I'm guessing that the problem is somewhere else. I'm completely stumped and about ready to just give up and take it to the dealer. Anyone else have any ideas/suggestions before I do that? Thanks again for all the help, Dave

Well, I am no expert but doesn't that refer to one of your oxygen sensors? RayO would know more but there are ways to test them. I don't know if you have multiple sensors in your car or not. Usually you have two. One before the cat and one after the cat. I believe PO141 probably refers to a specific sensor. From there, you can do certain tests to verify whether or not the sensor(s) are bad or the cat is bad. Probably just a bad/delayed/faulty O2 sensor that just needs replaced.

I believe I had that code and my front O2 sensor was bad. Replaced it and that code went away.

The description of the code is "Post-convertor O2 Sensor heater or circuit fault" and I have actually tried replacing the O2 Sensor with a Bosch and a Denso replacement part and neither of those fixed the problem. I did tests to make sure that the wiring was fine and it all appears to be ok, so that's why I'm stuck without any ideas of how to fix it but I'm definitely open to any and all suggestions. Dave

Can you verify whether the cat is good? Cats rarely go bad but I suppose it's possible. It may even be under warranty as I think they have an 8 year, 100k mile warranty or something.

After you replaced the O2 sensor, did you reset the computer so that it can re-calibrate?

I actually had the cat changed during this whole process and I have cleared the computer and unplugged the battery several times and the code always comes back. Dave

Where are you located?

To answer your questions, I'm in Tucson, AZ.

But as an update, I took my car to the dealer this week and they said that they ran some diagnostics on the old ECU and the new one that I had put in. The diagnostics showed that they were both bad. I had them put a new one in and the car is now running fine with no codes. Unfortunately, it cost $500 for the new ECU, but I was sick of dealing with the problem and I'm glad that the problem is finally fixed.

Thanks again everyone for all of the help, Dave

You should consider playing the lottery if you ended up with 2 bad ECU's.

We just moved this last week and you don't even want to know half of the list of "bad luck" that's happened to us during that whole process, so may I should go buy a lottery ticket just hoping that a run of "good luck" will even it out.

But the most frustrating part is that if the ECU I had gotten was fine, then I'd be $800 richer right now. But I guess that's just the way the cookie crumbles and at least my car is finally working again. Dave

Dave,

Thank you for the update. It is good to hear that the problem is solved, and I hope it is a sign of a run of great luck for you.

If you were in the Chicago area, I would have looked at the car myself.

Thanks and I am very grateful to everyone that helped me out during this process. It's been a little frustrating at times, but I've learned a lot and I definitely couldn't have done it without all of the help from everyone here. Dave

Ray you tried to help people and I'm all for that. It's just that with your automotive background and still not know how to properly diagnose this problem was a disappointment.

For example, Dave didn't need to get that third (?) Denso sensor at all or even any new sensor now that the problem seems to be with the ECU. And I hope Dave didn't use the parts store as a test bench. ;-)