I got my 2000 Blazer back in April and after O drove off the dealership lot I went to a gas station to fill up. I have or had a habit of always topping of my vehicle.well I was told that topping off my blazer will set off the SES light, which is on and on continuisly and not flashing. if topping off the gas the way I did set off this light then how do I reset that light to turn it off.please don't anyone say black electrical tape

 

get it scanned and find out what the codes are and report them back here. There is a reason it is on and I'd bet it has nothing to do with your 'topping it off' unless you have a defective part in the gas circuit. JP[sm=alien.gif]

 

Yah you should have the code retrived I dont think topping it off will cause a code to be generated. The gas cap not being tight will though. If the problem isnt still present many codes will clear themselves after a few driving cycles.

 

I say it is the gas cap. Mine had a similar issue, I read the codes, one was EVAP, plus some other speed sensors. But once it was reset, it never came back on.

 

Topping it off COULD possibly trip an SES light but not specifically for that. If you continue putting more gas in after the pump automatically clicks off, you are forcing more gas and vapors into the tank. EVAP is part of it, yes. Not sure of the reasoning behind it but I put the nozzle back on the pump after the first click for this very reason.

 

The reason is that fuel can be sucked into the EVAP system. It is a sensitive system. Too much over filling of the tank will saturate the charcoal canister, triggering the SES light.

This is all speculation without the specific code that was set.

 

I've been topping off ever since my gas guage took a dump about 5 years ago and it has never thrown an evap code. Go down to your nearest AutoZone and have them check the code. Then go from there.

 

I actually had the same thing happen to my Blazer. I topped it off and a couple days later, SES came on. Took mine to my local advance auto parts store, used their OBD 2 thing and it came up with a PO442 code, which is a small evap leak, which can be cause by a loose gas cap, or as Kyle said, you can soak the canister. It's easy to go to a parts store, use the OBD thing and reset the computer, but until it's fixed, the light will keep coming back on. I've been dealing with this for months but haven't gotten time to fix it. I think Kyle put up a post on the PO442 code on the forum so check that if that's the problem.

 

The most common cause of an EVAP code is the gas cap either being not tightened properly or having a bad seal. The second most common cause is a dirty vent solenoid which has been covered in a few other posts.