My SES light will not come on, and neither will my low coolant light They both come on when i first turn the key before starting it, so they are not blown out. But I had run out of coolant and the car overheated and the light never came on and I started the car without the MAF or AIR sensors attached and the SES light didnt come on. I have a 94 and on my buddies 97 the SES light came on without those sensors plugged in.

So what gives? Should I be worried?

 

if the lights come on during bulb test your ok.. but as for the low coolant light the sensor in the radiator might be bad.

 

definitly the sensors

 

so if i have my MAF and Intake air temp sensor unplugged then that shouldnt throw a light on the dash? because it does not, and on my buddies TA it does...

 

The IAT will only set the SES if it is above 293 degrees F. By disconnecting it, you made the resistance seen by the PCM infinate. This would make it seem as the the temperature were -40 degrees. However disconnecting the MAF should have set the SES light. But, I do not know how long the engine should run before the code is set. You should concentrate on this circuit to find if there is a problem.

Check the 3 connections at the MAF to see if they are connected correctly. The yellow wire should be 4 to 6 VDC. The pink wire should be 12 V and the blk/wht wire should be ground.

The really puzzling thing is if it is disconnected, either the signal going to the PCM is tied high (yellow) wire or the PCM itself is defective. This is interesting and will require more research. I wonder if when the engine overheated, if some of the wiring got melted????

Let us know what you find.

 

ya thats what I was thinking, right now its developed a coolant leak that I am more concerned with at the moment argh

If I unplug theMAF sensor with the car running it will stall, but even then it wont throw a check engine light

Is there any other easy way of setting a check engine light? Just so that I can see if thats the only thing that is wrong,t he other thing it does is the fan comes on within 10 seconds which seems to indicate its in "limp mode" but again the car is running good and no lights on the dash.

 

Have you ever put a scanner on it, to see if any codes for the MAF or IAT sensors were "stored" in the PCM?

 

no I dont have one, its due for an oil change in another 600 or so miles so i'll ask them to do it then.