Malfunction Indicator Light
This light is a part of an Onboard Diagnostic
System called OBD II that monitors engine,
and automatic transmission control systems.
The light will illuminate when the ignition is in the
ON position before engine start. If the bulb does not
come on when turning the key from OFF to ON, have
the condition checked promptly.
Certain conditions such as a loose or missing gas cap,
poor quality fuel, etc. may illuminate the light after
engine start. The vehicle should be serviced if the light
stays on through several typical driving styles. In most
situations, the vehicle will drive normally and will not
When the engine is running, the “Malfunction Indicator
Light” may flash to alert serious conditions that could
lead to immediate loss of power or severe catalytic
converter damage. The vehicle should be serviced as
soon as possible if this occurs
here´s a manual how you can find out what´s wrong with your jeep.
read out the error code and you will know what´s wrong:
1) Turn the ignition key ON THREE TIMES in succession:
ON : OFF : ON : OFF : ON
(within FIVE seconds)
2) Count the number of times the check engine lamp on the dash flashes. The number of flashes represents the error code. There will be a short pause between the flashes representing the different digits of the code. Longer pauses separate individual trouble codes.
I think on 2001 and up tj's with the digital odometer you just need to hold the odometer button in when you turn your key forward one click and after a couple of seconds it will start displaying your diagnostic info.
I have a ScanGauge in my motorhome. They work great! Very nice to have, you can adjust your driving to maximize your gas mileage. Really helps in the motorhome, I can see how it would be an asset in the Jeep as well.
After I checked the forum, I tightened my gas cap.. It was well-tightened.. I tried the turning the 3x's key turn trick but it didn't work for me.. I didn't get the chance to try mud707's method (because i do have an '03) before the light went off. What will happen if I try this method with no indicator light on? Will my odometer display a code if everthing is ok?
It will read your software version, then any codes not sure if any codes will flash for o.k. and then do a instrument dash check where your speedo and stuff will move up and down by there selfs. I did it to my brother's Rubi and he flipped out cause he thought I broke it before I told him I was just messing with him. It is something newer jeep owners should check out and learn how to do instead of taking it to the dealer and paying $90. for them to do the same thing.
"It is something newer jeep owners should check out and learn how to do instead of taking it to the dealer and paying $90. for them to do the same thing."-well said mud707.. no one has to tell Chrysler we live in a knowledge-based economy..
erickpl - I didn't notice anything substantial.. it does seem to hesitate a little @ about 50mph going up hill or on steep grades.. This may just be the way it's geared though considering i have an auto tranny w/od...
Take it to Autozone and see what codes it is throwing. I'd be willing to bet it is a simple exhaust sensor or the TPS or something that you can fix yourself quickly and relatively cheaply (around $100 or less).
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