I have a 98 5.4l Expy, and the check engine light came on the other day. I went by AutoZone and the I had the following error code:

P0455 Evaporative emission control leak (Large).

After a little research on this board and other resources, I discovered that my gas cap not being closed properly was causing this. A few days ago I had my truck washed, and while I was there I had them put gas in it. Evidently the "petroleum engineer" was "gas cap challenged", and didn't get it back on correctly.

Now that the gas cap is properly closed, the check engine light won't go off (after two days). Is there a way to reset this light, or do I really still have a problem.

Thanks!

Sam

 

Good question, my check engine light came on this past Friday. I let my truck sit over the weekend and come Monday morning the light was off. Autozone checked it and I had a P0153.. slow to test O2 sensor???

Sorry I couldn't be of any help to ya...

Big Mick

1997 Expedition XLT
K&N Air Intake
Hellwig Anti sway bar
Flow master
Plus extra mods.....

 

The only way to reset the light is to either reset the computer, which I think you can do by disconnecting the battery for about 10 minutes, or Autozone should have been able to reset the MIL (Malfunction Indicator Lamp).

 

Yeah, but then you have to reset all the radio stations....
- for those sensitive ones, that was a joke, ha-ha ;-)

Looks like your vehicles uses the ODB-II system (If you buy one ask for the one that is compatible with your truck). It will have a feature to reset the indicator. When I get a new vehicle I buy a repair manual, code reader (if I don't already have one) and the factory CD (from e-bay for a lot less money than from the dealer). I find I do not have to use them very often, but when it's needed it sure is easier than a trip or two down to the parts store.

Besides the radio buttons, power cycling the computer will erase the recent driving and engine starting history from continuous memory (the computer remembers the last 80 engine start/driving sessions). You should drive your truck for about 10 miles with at least half at highway steady state throttle, restarting your truck at least once in that first 10 miles. That gives the computer something to average with your next driving session.

 

You can reset the SES light or MIL by pulling the battery connection, but the down side is you will loose all your station presets on your radio and when I did it mine the fuel mileage sucked for a while. (no punn intended)

The best way is to use an OBDII scan tool to erase the codes. You can purchase a decent handheld one from autozone for $150, or I think they will clear them for free... But I have not tried. Also the light will reset itself automatically after (40) start cycles of no error codes.

But, the best way it to use a scan tool.

99 F250SD EC 5.4L 3.73 285 BFG/ATs...
99 Expy EB 5.4L

 

When I started my truck this morning the Check Engine light was off. Did it reset on it's own?

Sam

 

I have disconnected my battery at least three times in the past year and have never lost any of my radio presets. I even had a new amp (two separate occassions, the first amp was bad) installed at a shop and when I picked up the truck several hours later all of my presets were still working...and I know that those clowns didn't take the time to memorize all of my presets and reapply them to the approrpiate buttons. HMMMM