My beautiful new sweetheart drives and loves her 2004 Bonneville SLE. "I own three Pontiacs" This one has a little issue. the service engine soon is lit up and I had the dealer check for codes and there are none. The engine runs great and seems to have no issues other than the light being on. Also the fuel level sending unit seems to be on the fritz. I need to replace it. Any suggestions on that and is there a way to clear the service engine soon light.

Thanks in advance.
Michael V.
69 GTO
72 Lemans
75 Trans Am

You can try a new gas cap. Some times a bad cap can trip a light.

What exactly did the dealership say? Just to clarify, this was a GM dealer... correct?

Even still... if the gas cap was messed up, yes it would cause the light on but would as well throw a code... it causes the tank and the fuel system to not pressurize the way it should and will throw a code... not sure if its a lean code or one of its own but will have something

As well... a certified mechanic with a scan tool or ANY gm dealership should have had at least 1! code if the light is on... and if not should have cleared it to get it off...

so as previously asked... what dealer/shop did you take it to??? even the lower quality scan tools at parts stores (ie. O'reillys, Autozone, Pep-boys, Advance, etc...) should have been able to get some code or cleared it for you

The gas cap is the only thing I can think of that may not give a code. Everything else will have a code. Possibly they don't know how to work the reader.

That`* why I was wondering where the work was done (tech may not be familiar with the scan tool or, if aftermarket such as SnapOn, may not have selected the correct vehicle). Generally speaking, I don`t know of any vehicle of that vintage (not to say there may not be some) that would activate the MIL indicator and not set a code. If it is the fuel cap, there should still be an evap code of some type.

I took it to a Pontiac dealer to have a new keyfob programmed for the remote entry. While there they used a Tech II to program the key and I had him check the codes. There was none. You think he would have tried to clear it wouldn't you?

Yep. They should have tried to clear it. But, if it really is not a DTC and it'* something else, then it would not be able to be cleared via the Tech II.

You might have a dash cluster or circuit board issue here. You are getting a low fuel or no fuel showing on the dash gauge and an SES light.

Maybe ddalder can get back in here and offer some 'electrical wizardness' suggestions.

As Purple says, there may well be something such as a circuit failure going on here. My concern is whether the technician actually scanned the vehicle properly. With this vintage of car, you can go into each module independantly and scan only that module looking for both current and historical DTC`* (although there are seperate menu items for scanning these). You can also do a general Class 2 circuit check in which the Tech 2 will scan all modules found and display the number of DTC`* associated with each. When you know what modules have associated codes, you can then scan each module independantly to determine exactly what those codes are. My concern is that the technician may not have scanned the correct module and therefore didn`t find a code. The better approach would have been to use the second method I mentioned. You can`t just `turn off the light` without clearing the associated code. If there truly is no code that requested the MIL (Malfunction Indicator Lamp) it could be a number of different things.

I would assume that a technician at a Pontiac dealer would know how to do this, but I also know that on several occasions dealerships haven`t been able to correctly diagnose or troubleshoot problems. Just because they`re a dealership doesn`t mean they are incapable of error just like anyone else. You may have just had a very novice technician. Menus on the Tech 2 vary quite a bit from one vehicle to another and even one model year to another. It may have been a case of not navigating the menus correctly.

There is generally an option for `Clear all DTC`*`, but again the Tech 2 is simply going to clear the code it finds. If there is no actual DTC, this isn`t likely to turn off the MIL.