I have a 2000 LS ext cab. I had added some aftermarket stuff such as hypertech chip, and also switched to synthetic quite some time ago(around 20k mi.) The mileage is now 100k, and I have just recently switched the transmission over to synthetic. The day after I had this done, the service engine soon warning light came on. My truck is in outstanding condition(or so it seems). Could this warning light have come on as a result of the transmission switch to synthetic, and possibly just needs to be reset.

I have a 2000 LS ext cab. I had added some aftermarket stuff such as hypertech chip, and also switched to synthetic quite some time ago(around 20k mi.) The mileage is now 100k, and I have just recently switched the transmission over to synthetic. The day after I had this done, the service engine soon warning light came on. My truck is in outstanding condition(or so it seems). Could this warning light have come on as a result of the transmission switch to synthetic, and possibly just needs to be reset.


Who know's with these computer's what triggered the SES. You need to pull the fail record and find out what's it telling you, before I can give you any advice.