Question: I have a 2000 F150s/c 4x4 with the 5.4..... the service engine soon light came on 1/2 from minnesota to daytona for the 500, made it there and back no prob and have driven alot and the light refuses to go out, the manual says it may take a few cycles to go out...but hasnt, is there a way to reset it maunally? thanks for any help! it has about 104,000 on it. Rich

 

Your SES light came on for a reason, it's not going to go out by itself. You have to have your truck scanned for codes to find what the problem is, repair it and then have the codes cleared. Autozone stores will scan your truck for free (except in Calif.)

You can manually clear the code by diconnecting your negative battery cable for about 15 minutes thereby resetting your computer but chances are the light will come back on shortly because of whatever malfunction caused it to go on in the first place.

 

Plus driving around with the light on means that your engine is running in a limp home/open loop mode so your mileage will suffer

 

My money says its O2 sensors... please let us know

 

My money says to get the codes read and don't guess.

There are hundreds of possible codes. Feeling lucky?

Steve

 

Hello there,

Sorry for the delay but got the code read today, it is po125 insufficient coolant temp for closed loop fuel control, sounds like a bad sensor because theres plenty of coolant in it and the dash gauge reads in its normal position.....anyone have any ideas? thanks for the help!

Rich

 

If the coolant level is ok. Replace the thermostat. 99% of the time a PO125 cause by a thermostat that is or was sticking open.Even if you temp. gauge shows normal, at one time engine temp didn't warm up quick enough.

 

could be your coolant temp sensor too - had to replace mine...

 

Furbugl, could you tell me where to find the coolant sensor? thanks for your help.

Rich

 

A 2000 5.4L doesn,t have an engine coolant temperature sensor, it has a cylinder head temperature sensor.This CHT sensor replaces the ECT SENSOR. The CHT sensor is located under the intake manifold,in the front of the left head. The reason for the CHT is it measures actual head temp, not coolant temp. If an engine is run low on coolant an ECT can't measure air that is in coolant camber, but the cylinder head temperature is accurate with or without coolant.GOOD LUCK ON THAT 1% SENSOR CHANGE

 

Hey 80Yama, did you ever find out what was tripping your Service Engine Soon light? Was it a bad thermostat? A coolant temp sensor?

Thanks.

Pete

 

Hey pete!

Yup got it fixed this weekend, replaced the thermostat on thursday and after a few cycles the light finally went out saturday evening, the other day at the dealer i asked a tech what a po125 code might indicate and with out even thinking he said thermostat, he said they did like 5 trucks with the same prob in the last week! are you haveing a prob with yours? thanks for everyones help!

Rich

 

Those check engine lights are tricky. Mine was flashing on and off. When I took it in for the oil change, they said that air filter needed changed. After they changed it, it never came on again. I never knew the air filter could trip the check engine light, but I guess if the engine is not getting enough air, it will cause funky things to happen.

 

Hey 93_snake,

I have heard that a blinking SES light means thats theres a miss fire in the engine?? as a matter a fact if i remember right the manual says that also, maybe being dirty can cause a miss fire??

Rich

 

>Your SES light came on for a reason, it's not going to go out by itself. You have to have your truck scanned for codes to find what the problem is,<

Instead of a SES light, why doesn't the actual code display? At least then the driver can get an idea of what is wrong. I wonder if they want you to bring it in for for a diag. charge?

Thanks Bob