Just a reminder for car owners......Service Engine Soon Light

This was posted on at the tail end of another thread....but wanted to pass along some lessons learned for those that missed it.

"Check Engine Soon" light came on, on the 1999 Ford F-150.

As most pf my vehicle work.... is no longer something I look forward too.... or able to handle, because pf the computers, and special tools need to fix things.

Light came on, so called my dealer...good service so far.......explained what was going on.....and got a
"Well we can't get you in for a diagnostic check till next week (7 days away).....and that will be $100 buck for the check.
And as the truck is older...parts may need to ordered...and have to wait for a "fix it appointment.

So I asked them why they didn't have me stop by, plug in the computer checker...then form a game plan..as they had done in the past.
They said they were real busy (?)....But a week to start with, was out of my time window .....This is a around town ride....wouldn't hurt to leave it sit.

As the members of WSF had talked about this on that other thread...and a couple of things popped up....
Auto parts stores will do a computer check for free....Auto Zone did....

Print out says Gas cap primary cause ?...What does that have to do with anything?
So a new gas cap was $15 bucks....so I bought one and kept the print out.

Resetting the computer can de done by disconnecting the battery for a while...20 min was suggested.

Tried it....so far so good....may need another service call....We will see.

just a FYI.

I had a Dodge Caravan that disconnecting the battery resulted in the gauges going into the twilight zone. You had to go through a set sequence like push in the Trip B button Turn the ignition to On, Open the Glove Box three times, Hold your left foot in the air, Spit out the passenger window. Really dumb stuff for the gauges to go back to zero. You NEVER wanted to unplug the battery on the vehicle. EVER. I once had my vehicle service and went in to pick it up. The entire service team looked like a Chinese acrobat team. I asked them what was going on and one of them said the mechanic had unplug the hot lead on my battery. They were hanging everywhere on the van.

My Jeep does not have that problem. All I have to do is reset the clock.

Just disconnect the battery, wait ten, then hook it back up.

One of the things that keeps the older rigs, 15-20 years, going for so long is the fact that many times the simple repairs we do require disconnecting the battery for safety reasons. Every time we do that we are resetting the computer to the factory default setting and basically doing a "tune up" of the electrical system.

I drove the Jeep for over a year with out a single problem and then BAAM! it stops dead in the middle of the road. I whine and worry and do this and do that and finally run the battery down. I disconnected the cables to run the battery charger, hook it back up and it runs like new! I suddenly realized I had reset the computer. It needs a new brain, and a new one is not all that expensive, but I will streach that purchase out for a while.

The gas caps are now part of the emissions control system, and if the cap has a cracked seal, the computer sees it as a "leak" in the system and turns on the engine light. Can't have gas vapors escaping to the air.
A lot of times, the check engine light will turn off by itself after a certain number of miles if the offending thing is corrected. They have an auto reset at something like 200miles.

I had a mechanic tell me after 7 check cycles. Who knows?

I've been lucky so far with the lack of check engine light coming on. Two of the three trucks I own do not have gas caps.

With Subaru cars, it's the first thing you check. Even putting it on wrong at the pump will turn that darn light on.

As mentioned, it is emissions for the gas cap.

I bought a cheap OBO 2 reader so I can run my own code checks and reset the light. For $20 you can get the reader and know what is going on without having to pay fees and you can reset the lights without needing to see a chiropractor afterwards.

My Envoy had similar issue with gas cap if it's over tightened or misaligned, all I had to do was unscrew the cap then put it back on the correct amount of clicks

Those dealer fees for a simple code check are the worst. I bought a cheap reader myself, and it has saved not only my, but also several friends and coworkers, a lot of hassle. Especially newer cars (I also hate how much the electronics systems are making things much more difficult to fix in the driveway) with so many sensors that the codes can be very specific.

Auto Zone did mine for free ....So one less tool I have laying around that I won't use much).......
It provided a printout of most likely causes......and sold me that cap for $15 bucks.....
All better now...
Moving on to the tractor..... won't start.

Planes are like that. If you're on the ground, sometimes a reboot will fix the problem. If not, expect a delay. You have to turn everything off. That also means you will have to input all the flight data again and that takes about 20 minutes. Needless to say but, in the air you can't reboot. Just isolate the computer and let the others pickup the duties.

Tractor back up......was a wire wiggler trouble shoot and fix.....then pulled a solenoid wire off and cleaned it.
We will see.....

I realize this is an older thread but a continuing problem for many. A suggestion. The sensor that monitors the amount of air and gas mixture s called a mass airflow sensor, MAS . It is located in the air tube that goes from the air filter to to engine. Remove negative battery cable. Find your air filter, the MAS is the sensor with probably 4 or 6 wires on it next to the cover . Unplug it . Loosen band clamp next to it and remove the air tube. The MAS has very fine wires that hang down into thr tube . They get dust and residue on them and give inaccurate readings, giving you a warming and need to be cleaned. All auto store s sell MAS cleaner or electronic spray cleaner can be used. Spray the sensor probes clean . In short remove air cleaner cover, MAS can usually be seen. Spray it down. Put air cleaner cover on. I think This should always be done after any service light repairs . A lot of time it’s an oxygen sensor reading meaning an air fuel mixture problem which can get expensive when it was actually just a dirty sensor gibing bad reading. I always clean sensor first. Hope this helps.

I drove a Toyota T-100 for 150,000 miles with the "Check Engine" light on. Near as I can tell, it's a light.

Alan