Please HELP!

[Seagreenmachine]

I have a 2006 Chevy Aveo LT. I had my check engine light pop on a few weeks ago and had the codes read immediately-- P0420, P0700, and U0073. I know the P0420 is just my downstream 02 sensor as I was told this by a mechanic when it first popped on like 3 months ago but he had cleared the code. Last weekend we took our car to the Transmission shop to have the other two codes properly addressed and they said that there is a leak in the Water Pump and it needs replaced, and there is a leak in the oil pan and it needs replaced and there is a leak in our rear gasket between the motor and the transmission which needs resealed. Total was going to be about 1200-1600. Is there any piece of this I can do myself that might be easy to get to and change? (weekend job)? I was thinking the water pump and oil pan wouldnt be too hard. What do you know about replacing the O2 sensor? Is it pretty straightfoward? Any problems you guys run into or should I just run with that price and let the mechanics do it?

Thanks

[avguy]

Wow, you have been given some surprising information by the pros - not saying any of it is wrong, but it is a bit unusual.
First off, the P0420 is a code which indicates that the O2 sensor cross-checking is finding the cat to be performing below minimum spec. Now it's very common, especially for amatures like myself, to just hang on an upstream O2 sensor hoping that it's a bad sensor instead of the cat. That would be a much easier and less-expensive outcome. Sometimes it works and sometimes it doesn't. But I don't understand how the mechanic could know the problem is the O2 sensor without swapping it out. That being said, I would agree that the sensor is a good try, and would do that myself. This is a very easy DIY on our Aveos.

What the transmission guy said is even harder to understand. P0700 is the general transmission code, and it means that transmission-specific codes have been set and need to be read with a TCM reader. So if he did that and maybe also read the CVIs, then one would expect to hear about a transmission-related problem. But oil and coolant leaks? Are you sure this was a transmission shop?

I can't speculate on the rear seal leak, but I've eliminated oil pan leaks by just snugging up the bolts (not overly tight just snug). I can't imagine knowing it's a water pump leak unless the timing belt cover was removed and he could actually see water inside. Just a drip off the bottom lower timing belt cover could be coming from other places, in particular the plastic thermostat housing which is notorious for cracking. So you need to confirm for certain where that leak is coming from before messing around with the water pump (which is NOT a fast and easy DIY on the '06). You can try asking him specifically how he determined that the water pump was leaking. Do you know when the last timing belt change was done, and if the water pump was done at that time as well?

In addition to confirming the source of the coolant leak, you also need to get the P0700 diagnosed by someone who reads tranny codes - there will be one or more additional codes to evaluate once that is done. Good luck getting all of this sorted out!

[Chevy Customer Svc]

I have a 2006 Chevy Aveo LT. I had my check engine light pop on a few weeks ago and had the codes read immediately-- P0420, P0700, and U0073. I know the P0420 is just my downstream 02 sensor as I was told this by a mechanic when it first popped on like 3 months ago but he had cleared the code. Last weekend we took our car to the Transmission shop to have the other two codes properly addressed and they said that there is a leak in the Water Pump and it needs replaced, and there is a leak in the oil pan and it needs replaced and there is a leak in our rear gasket between the motor and the transmission which needs resealed. Total was going to be about 1200-1600. Is there any piece of this I can do myself that might be easy to get to and change? (weekend job)? I was thinking the water pump and oil pan wouldnt be too hard. What do you know about replacing the O2 sensor? Is it pretty straightfoward? Any problems you guys run into or should I just run with that price and let the mechanics do it?

Thanks

Are you working with a GM Service Center or an independent mechanic? If the former, we're available to check into this further with you and your dealership!

Regards,
Sarah (Assisting Jackie)
Chevrolet Customer Care

[ch3mw4r]

Reviving this thread. I'm getting a P0420 myself right now, and GM referred me to my local Chevy dealer to see what the code is for (I know it should be the cat). GM told me the cat converter for my 2010 aveo is covered until 2018 or 80k miles, and I'm at 77735. The dealer told me though that if the problem isn't covered under warranty and a tech looks at it, they'll charge me $100+tax for labor and let me decide whether they fix it or not. So basically I have a chance to run myself out an extra $100 for a tech to look at the thing if it's not what the ECU says it is.

[Daox]

You mean P0420, right? Chances are its not the CAT, its an O2 sensor.

[ch3mw4r]

Aye. I edited the post to correct the code. Is there any way to tell for sure that won't cost me a fortune first? Basically, I want to find out what the problem is and if any warranty covers it. I would sincerely hope that at only 3 years old my car shouldn't be having these problems. I don't want to bring it to Chevy and them tell me it's the O2 sensor and charge me $100 just to tell me that basically. I'm actually hoping it's the cat because that would be covered.

[avguy]

It would be unusual for a cat to go so soon, and typically it takes a good deal of raw gas to trash it kaput. Did you ever have a bad misfire that went on for an extended period of time? If not, the usual choice is to either hang on a new upstream O2 sensor, or (better yet) remove and test it. Replacement is an easy DIY, if you're up for that. For testing it, you would need to find the test specs for the factory sensor, which I have not seen in print, and is probably only found in the FSM.

[ch3mw4r]

It would be unusual for a cat to go so soon, and typically it takes a good deal of raw gas to trash it kaput. Did you ever have a bad misfire that went on for an extended period of time? If not, the usual choice is to either hang on a new upstream O2 sensor, or (better yet) remove and test it. Replacement is an easy DIY, if you're up for that. For testing it, you would need to find the test specs for the factory sensor, which I have not seen in print, and is probably only found in the FSM.

This was the only CEL I've had on it, I've never had a misfire code, at least in the 7 mos I've had it. What does testing the O2 sensor take to do? I've got a bit of equipment and my appointment at the Chevy dealer is a 2 p.m. tomorrow.

[Chevy Customer Svc]

Hi ch3mw4r,

I just want to clarify this for you. Once the vehicle is out of it's Bumper to Bumper Warranty the dealerships do charge a diagnostic fee. That fee varies by dealership. Typically the diagnostic fee that is paid goes towards the cost of the repair if you choose to get the work done at the dealership. If the issue was covered under the warranty the diagnostic fee would be refunded to you. The only way that you would be out of the diagnostic fee is if you got it diagnosed and decided not to get it repaired at the dealership that you took it to. I hope that makes sense. If you would like I am available to call dealerships and get diagnostic fees for you. There may be a dealership in your area that has a lower diagnostic fee. Please message me if you are interested in me calling to find out this information for you.

Jackie
Chevrolet Customer Care