How do I reset the Service Engine Soon lamp on a 1999 F150?

Thanks!

 

Have someone with a diagnotics tool reset it and pull the trouble code to find out what is wrong for free or do what I do and disconnect the battery for a few minutes to clear the computers memory and dont worry what the problem is. Ha Ha.

 

It came on at exactly 60,000 miles so I assumed it was one of those automatic reminders to get the catalytic converter serviced. I'll have to try the battery trick and see what happens. Thanks.

 

Why would the cat converter need to be serviced now?

Exactly...I think you need to give up on guessing and take the truck to get code scanned.

Those maintenance interval timers are long gone. OBD2 tells you EXACTLY when something has gone wrong, not just some guess at a given mileage.

Glad to clarify things in an attempt to keep you from pulling the ECU fuse or battery cables only to come back wondering what is STILL wrong with the truck.

 

like them or hate them, autozone will scan your computer for free and reset the light if it is nothing major, some of the stores even hand you the scanner and let you have at it if you ask them.

i would scan it, research the code and if no big deal, clear it and see if it comes back.

 

What are the possible problems? Fuel system seems OK, no leaks, cap is on tight, mileage and performance of the truck hasn't changed. What sort of attributes does the system check?

 

About a thousand things can make the CEL light come on. Once mine came on because I did not put my gas cap on all the way. The scan tool even told me to put my gas cap on tighter. But not in so many words.Thucks and thier computer systems these days. Hook me up with a 55 Ford any day.

 

well the newer systems check everything way to long to list here, and your performance and gas mileage hasent changed becuse the computer compensates by takeing whatever is wrong in your truck and changeing outher computer controlled devices to kindda correct for the problem so your gas milage dont go to **** and your not chugging down the road wondering if you can make it to a service station. but still the problem still is there and if you let it go you are posabilty damageing the outher componets that are compasiteing for your orignal problem.

 

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How to turn off the light:

Disconnect the battery for a few hours, and reconnect.

Why the light is on in the first place? Pull the code(s) with a scanner.

artk.

 

Thanks for the help. The truck is soon to be replaced with a F250, so whether I decide to make the permanent repair depends on what it is and what it will cost. This truck has been great, 6 years and no major issues, pulls a boat well beyond its rated tow capacity (short distances of course, 2-3 miles) but has no problem pulling it off the ramp. I'll have the lamp diagnosed next week.

 

Interesting thing happened to me today, and has almost nothing to do with this thread, but needs to be said, I think...

My sister's (my) '96 t-bird 4.6L had a tune-up done. For whatever reason, the mechanic disconnected the battery, clock was reset, radio presets were gone, etc.

I checked it out with my Autotap, and no codes. All diags passed too.

Had a problem idling, just like it always did when the computer was reset. For whatever reason, it wouldn't idle in gear until it "learned" - or, all diags were passed.

I did a "Clear DTC's" and all of a sudden, all diags were NOT passed. Took it out on the highway and drove it for 30 minutes, everything passed (cats still needed to pass, but that's OK). Idled fine.

What I'm trying to say is, even if there are NO codes according to the scanner, something may still be up, and a "Clear DTC" is in order no matter what.

Now, what's funny? The battery reset did NOT clear the condition! I had to use the scan tool, and it reset. Same thing has happened with my '01 V10. No codes, but clearing them made the computer reset.

I think if you disconnect the battery for a few minutes, it "sorta" resets, but leaving it disconnected overnight really clears out the non-volatile memory, completely resetting the "learned" program.