it only comes on after 15 minutes on the freeway@75mph and stays on until i turn the engine off,then start it up and no light.what could be causing this?car runs great except for a high idle around 750rpms in drive and 1100rpms in park,gotta clean the throttle body again i guess.Thanks

 

what code are you getting?

could be a number of things........

 

can u pull the code while the engine is still running?i don't have a code reader,so i use the paperclip way,turn the ignition off and then back on and count the blinks.when i turn the ignition back on,there's no SES light or codes.Thanks

 

something is amiss right there then

 

what would be a couple of things that could cause it to come on at freeway speeds and not around town?

 

Yea..... but what code are you getting?

Anytime the SES light comes on, it stores the code. You should be able to get the code as long as you check it within 1 month of it happening.

Is it a code 32? You do know that the computer will blink code 12, three times before it gives you actual codes, right?

 

i didn't know it stored the code for a month,i'll check it out.thanks

 

i got 2 codes 32(EGR),45(Rich exhaust)my car does have a strong gas smell after drivig,would either of these cause my idle to go up?because recently the idle has jumped about 300rpm's in drive and in park.Thanks

 

Actually, there is no run-time clock in out older ECMs. A typical ECM will store error codes for the last 50 or so engine run cycles, depending on how much integrator data has been generated and moved to BLM tables and how many error s have been logged. 50 is usually a good estimation. That could be a month for some. That could be a year or more on some of my vehicles.

The '32' is likely what is setting the SES as you drive at moderate load and freeway speeds. It's typical of a failing EGR valve or solenoid. It could also be a diagnostic temperature sensor on the EGR valve base. You can use this flowchart do help diagnose your EGR problem:



Take care of the EGR problem first, then attack the '45' if it still exists.

 

thanks for the chart Vader