I don't start a lot of threads here so I really don't know if this should be here, if its in the wrong spot maybe someone will move it.

A month or so ago the CEL came on while I was in Wisconsin. I stopped at a nearby O'reilly's auto parts store and the dude plugged in a code scanner and told me that the computer had detected an exhaust leak.

He reset the CEL and I went on my way. I started checking around for exhaust parts. I'm still looking for an affordable system so I haven't fixed it yet.

The thing is the CEL came on again the other day. I figured it was just that it had detected the exhaust leak again so I took it to an Autozone parts place and even though the CEL is still on the scanner they used says no code returned.

The dude didn't know what to make of this. He said there is always a code when the CEL comes on and that he could not clear the code if it didn't show on the scanner.

So I removed the positive side of the battery cables for 10 minutes. After hooking things up again the CEL stayed off until after I got home. I decided to look here on the HHR site to see if anyone else had a CEL on with no code returned but either I did not use the search function right or no one else has a thread quite like this one.

Just a little while ago my daughter went up to get some milk and said the CEL was on again. I called my younger brother who has an OBD II scanner and he came right over and again the scanner says no code returned.

I am left to wonder WTF??

I tried grabbing a hand full of wires and wiggling them to no effect. I tried unscrewing the fuse box on the passengers side of the console and wiggling wires there too.

The car seems to be running fine its just that the CEL keeps coming on with no code returned.

Any ideas?

 

The basic code reader only reads emission codes. If you have a fault code of some other kind like trans or body module the basic code reader won't read them.

 

That's why I went to Autozone where they have a bit more than a basic scanner.

But even their uberscanner did not find a code reported.

 

Please oh please, don't unhook the Positive cable from the battery under any circumstances, unless you have first unhooked the Negative cable.

Unhooking the Positive cable only can do serious damage to the various modules and sensors by hitting them with a voltage spike.

You should seek out a technician with a Tech II scan tool, these have the capability to see codes that are related to the TCM, BCM, and other modules not commonly "seen" by other code readers.

 

Suggestions; the failure to "return a code" is probably because the cig lighter fuse is blown. The exhaust leak in question is most likely the flex pipe.

Exhaust leaks can cause DEATH, you know.

 

I'm pretty sure the cigarette lighter fuse is good. I plugged phone into it today and the light on the plug lit up and it said it was charging.

I did a visual inspection on the exhaust system. The flexible part looks to be alright. I did find a small leak near the front of the muffler though.

My daughter used the car to go to Sterling today and while she was there she stopped at an O'reilly's and one of the counter staff put their scanner on the car and said it was indeed that the computer had detected an exhaust leak. She also said they could not just turn off the CEL unless and until the problem was actually fixed.

Not a real problem I guess, I know how to disconnect the battery terminal.

I still wonder why the code scanner at Autozone said no code returned though.

 

I'm going to get a little blunt because safety is an issue here - so please bear with me:

"I know how to disconnect the battery terminal." - no you don't - if you disconnected the positive terminal (like you stated earlier), instead of the negative one, you risked shorting the positive terminal to ground while trying to undo it.

If that happens, your wrench will become red hot before you can blink, giving you a nasty burn - or if it welds itself to ground, your battery can explode in your face.

It's not something to mess with if you don't know what you are doing.

Tip: always post the downloaded trouble code, not the description that the person that downloads the code for you - the description is often a general statement, whereas the code pinpoints the issue at hand.

You say it's not a problem living with the exhaust leak? Didn't you read donbrew's comment about exhaust leaks? You need to get it fixed!!!

Don't worry about why the one code reader could not read the code - not all code readers are compatible with the HHR - and you have more important things to worry about.

 

Wopper,

I do thank you for your concern about the exhaust leak and removal of battery connections.

I'm 60 years old and have been working on vehicles since I was quite young, my dad was a master mechanic even had certificates to prove it. Although I do not have any certificates from any factory training or automotive schools I do know what I'm doing most of the time. If I don't I will actually get a book and look stuff up online so at least I have a written description of what I'm trying to do.

I normally remove the positive battery connection when working on things that might be electrical in nature on a vehicle. Almost all the repair manuals I have ever read said to disconnect the battery before working on most anything on the vehicle.

It did not specify which battery connection to sever so I just started doing at least the positive side. It does make some sense to me that removing the negative connection might be better with the computers on board the newer cars though.

I used to have my own body, radiator, and general repair shop and I've worked in a few someone else owned as well.

I've seen guys actually blow up a battery or start a fire from not doing things right so I know there is some real danger involved especially for the uninformed {read that clueless.} I also know that just because it hasn't happened to me it still could at anytime.

As far as the exhaust leak goes, the entire exhaust system looks pretty solid. As I said there is a small hole near the muffler but that's all I can find. The Flex part looks to be intact and does not seem to have any detectable extra noise in that area. When I put my hand near it I did not feel any hot exhaust leaking out, the pipe was plenty hot so I was careful not to touch it. I have an inspection mirror on a extendable handle so I could look at the top of the pipe as well.

I have now properly jacked the car up and supported it with heavy duty jack stands on a concrete driveway and crawled {on my creeper} the entire length of the exhaust system with the engine running looking for leaks. There is a very small little bit of rusted/corroded weld on the inlet side of the the muffler but that is all I can see.

I'm beginning to suspect a bad sensor somewhere in the system.

I would really hate to replace more than what needs to be replaced on the exhaust system but the flexible part seems to be pretty cheap so I may just get one and go from there.

On the code scanners I realize that not all OBDII code scanners are the same and that there are more advanced code readers available. The guys at Autozone have always been able to read the codes and reset the CEL on the various vehicles I have brought them over the years. They were even able to diagnose the ABS on our Chrysler LHS. {that ended up costing me more than the car was worth} When we had the '92 Grand Am the alternator was acting up and the CEL would come on and there were no codes available. I found it with a little starter alternator meter thing I have. You just lay it on the wire and it will tell you if the alternator is alting or not. The meter would peg then drop to zero then peg again. Replacing the alternator fixed that.

I just think its odd that the scanner that O'Reilly's uses can read the exhaust leak but the one at Autozone does not.

The folks at O'Reilly's told me the scanner they use costs around $250 if you buy it from them. I'm giving serious thought to getting one.

 

Well, I guess you don't get what I was saying - you continue to remove the positive battery connection if it makes you happy - at least I tried.

Sorry, I am out of this one.

 

No I got ya just fine Whopper.

I'm not totally clueless.

I have done some actual school time studying electronics {I was unable to finish because I simply did not have the money at the time} I'm a amateur radio operator in my spare time as well so my education in things electronic in nature is on going.

Removing the power source is a basic concept that I do have a pretty firm grasp on and I shall endeavor to remove the negative connection on car batteries from now on.