I just had a question about my car. The S.E.S. light comes on after about 15-20 minutes of driving on the freeway. I know my air dam is bad and that is the only thing I can think of that is causing it. What else could it be besides the air dam? my car does heat up close to red on the freeway sometimes and I will get a new air dam soon but I was just curious to what is causing the light to come on. any comments or suggestions would help. Thanks

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1986 Pontiac TA 305 carbuerated.

 

TA - er, MR. TA,

I'm guessing EGR...

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Later,
Vader
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"I know how to solve your problem, but I can't tell
you since you might use the information illegally..."
Adobe Acrobat Reader 4.0

 

nope EGR has been replaced.

 

Oxygen sensor? After car runs closed loop and warms up it turns to open loop. If the oxygen sensor isn't working then it'll turn up that code. It does it in my mom's car after 15 minutes or driving in morning and if it's warmed up already it'll come on within 5 minutes. It's our POS car (92 grand marquis) so I don't feel like changing the sensor. Only problem is it runs a little ruff at times.

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, Jon (91 RS too many mods to list), getting new engine in summer

 

Check the code with the paper clip test. That will tell you if it is the o2, egr or something else. Just connect a paperclip in the top right two prongs in the plug under the steering column. Then put the car keys in the start position(do not crank) and count the blinks on the SES light. ex. l blink, pause, two blinks = 12 the ready code. Right down the number and let us know. It is really easy.

 

It's your CTS. If the ECM doesn't see the coolant temp come up to some reasonable value in some reasonable length of time, it sets a code.

Check the sensor, it's in the water outlet where the top radiator hose goes; it has a yellow and a black wire. Check the wiring first, then measure the sensor when cold and again when it's hot. It should go from a couple of k cold to a few hundred ohms hot depending on the exact temps. Those wires very often get trashed, and teh connector is a poor design such that it often makes poor contact, so I'd bet it's more likely the wires.

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"So many Mustangs, so little time..."
ICON Motorsports

 

i dont know how you guys can be throwing out ideas of what sensor to replace by the minimal info he provided.. no air dam will not throw a code.. how can you say egr cts or o2 when all he said is that his car overheats and ses light comes on,. the overheating is obviously becasue of the missing air dam. listen to Blue92 and check your codes.