CEL help

Anyone have the means to check CEL codes? I threw a CEL on the way home from work today. Didn't notice the car acting funny or anything. Had the AC on but my engine temp looked good. Only thing I did today that was a bit different was I overfilled my gas tank by accident while filling up. I checked to make sure the gas cap was tight and am now resetting it by taking the + side of the battery off. If it comes back anyone have any help to offer.


Thanks,

Mike

 

Hold on!!! You might want to stop yourself from touching the positive side of the battery. It has always been the negative side of the battery that needs to come off for an ECU reset.

It could have been the gas cap, but if it doesn't come back on after doing the reset, I wouldn't worry about it. ECUs nowadays are very sensitive, and will throw a code if something like a bug hits your windshield at a certain angle.

 

I have a cheap pocket scanner that I picked up at Checker for $40. Works well enough to get the codes.

I had a similar CEL that happened on hot days usually with the AC on, turned out to be the knock sensor, P0325. I just took it out, cleaned off all the corrosion on the bolt and the sensor and retorqued it and I haven't had any trouble since.

Joel

 

Cool thanks Fong, I just hate to leave it on, and I don't like spending $100 for the stealership to tell me nothings wrong, or it's somthing they can't fix.

 

Hmm where is the knock sensor located?

 

Driver's side, on the engine block, kinda right below where your throttle cables are. It's just held onto the block with a single bolt, has a single wire running to it. I can take a pic tonight if you have trouble identifying it.

 

That would be cool,

thanks,
Joel


I just cleared it, the stupid alarm scares the SH** out of me everytime I reconnect the battery. Hopefully it won't come back.

 

hehe my CEL has been on for over year now for a sensor i dont even have! dont worry to much bout it. alot of people here have readers. i am sure if you ask they migh thelp you

 

Here's the bolt that holds on the knock sensor. On mine the bolt itself had some corrosion on it. Also clean the top and bottom surface of the knock sensor and the spot where it makes contact on the block. I think the bolt should be torqued to 17ft lbs when you put it back on. A drop of oil on the bolt wouldn't hurt, IMO.

My car was fairly intermittent with this, it would go a few days without throwing a knock sensor code sometimes.

 

could be nothing or it could be something.. just cause one car throws a code doesnt mean your car wil lthrow the same... thats why they have their own computer to monitor stuff like this...

I agree the dealership robs people for doing checks.. we charge about $20 which includes printouts of the codes and diagnostic procedures to follow to fix printed out... checker will check it for free I believe...

 

If you clear the code then you won't know what it was. It's better to have it scanned first, then clear it if it's not a big issue or was most likely random.

Autozone will scan codes for free.

 

I also have a scaner too. Just codes though nothing too fancy. Read and errase.

 

most times it should still store it in memory as a hard code but will reset the light...

 

Every time I have done an ECU reset by pulling the negative terminal, the codes are gone and the light is turned off.

 

Damn, well I cleared it so I don't know what the problem was, but the light hasn't come back on yet so I'm not going to worry about it unless it does. I'm guessing it was either the gas cap or the heat. Thanks for the advice. I'll keep you guys posted.