My service engine soon light just came on when i was going up a medium sized hill in 4th. The motor was turning 2k and wasn't realy lugging. I pulled over and turned the ignition off and the light turned off. The guy i bought the car from said this happened to him a few times because the motor detects a lot of knock or something. It is hot still 82 at 9:30 here in wi and the humidity is also high so that might have something to do with it. What causes the light to come on and is this common with lt1's?

 

The PCM won't set a code or turn on the SES light for excessive knock.

Most likely cause, under the conditions you described, is the EGR valve. Seldom seen on an OBD-I car, but can happen. Getting an SES light while going up a hill is not "common" on the LT1.

But why guess? The code is stored in the PCM and can be retrieved with a scanner. At least if you don't wait too long.

 

we had a local guy with w v6 have the same complaint, no explanation yet.

 

I downloaded freescan so i just need to get a cable. Maybe i'll oorder one and try to scan it.