Is there any way to read fault codes without a code reader?

Is there any way to erase them and turn off the Check Engine light without a reader?

 

Do as stated above, but just don't actually start the engine when doing it. Turn it to the on position right before it cranks.

 

You will need a programmer to clear any codes. Either that or fix what is actually wrong.

 

do that then if it tells you any code write it down and just search: jeep jk dtc codes...then u'll know what they mean

 

Solid info. I agree 100%.

 

www.project-JK.com

Click on Jeep JK Write-Ups.
Under Troubleshooting is Diagnostic Trouble Codes - DTC How to Check Them & What They Mean

 

Thanks for the replies.

For some reason the check engine light went out today.

I must have that secret "auto fix" option

 

I go to the drive-in frequently and after sitting with the key in accessory to play the radio for several hours, when I start the jeep the check engine light and lightning bolt come on and the engine runs rough. If I turn the ignition off, then restart, the engine runs OK but the check engine light stays on. After a day or two the light goes off. the only code indicates an issue with the cooling system.

If after sitting with the radio on for several hours I first turn the key to off, then start the engine I get no lights and everything runs fine.

 

If you fix the problem the code will remain registered and the check engine light will remain lit.
However if you disconnect the battery for 2 minutes and reconnect it the check engine will go off and the code will clear, provided the problem is resolved.