jacksonbase

Cranked Cherokee this am and check engine light came on. I checked fluids etc all looked good. Runs fine no issues. I then took truck to 2 places (not stealership)with code readers and both told me no codes are showing up? I've never had a vehicle that didn't show a code when light fixes to on. Is there some kind of factory or dealership code reader? I was going to just unhook battery and see if knight goes away
Any thoughts?
Thanks

1999 classic 4x4 stock 118k miles

skife

depends on the code reader. If the light is still on, you may have to take it into a mechanic to get them read. (i've never had that problem)

also, if it's running good and all your gauges are fine, chances are it isn't anything that is going to cause long term problems.

DieselDaze

OP said he had it checked at two different places...

Disconnect positive terminal and place (hold) on negative terminal for 30 seconds.. Place positive back on battery start jeep and see if 'light' comes back on...

skife

they probably just used a code reader, not an actual scanner.
an actual scanner should be able to check stored codes.

also, was the check engine light on when the guy checked the codes?

DieselDaze

hmmm.. okay news to me...

the way I've always understood it is a code reader is to indicate what code is tripped when the "check engine light" is on...

a scanner is used to help diagnose the problem and has software to guide you through it, also can be used when 'check engine' light is not on where as a code reader cant...

in a nut shell the same thing, but anyone behind a code reader with sense wouldn't hook it up if the 'check engine' light wasn't on, so to answer your question I'm sure it was on