Had the check engine light (4L) come on after last weekend wheelin trip. It's a 1998 TJ, turned the key ON OFF ON OFF ON (a sec for each step) and nothing.... The MIL just stays on... Do all TJs have the ability to check the codes without the code reader? Am I missing something here...

I believe they did away with the key on/off trick on the 98's, but brought it back for the 2000's.

I'm not sure of what years have it, but I know that it was gone for a bit.

Darn! I guess I have to buy a code reader now.

Take it to any auto store (Checker, Auto Zone, Advance Auto) and they'll read it for free...

I have a 1998 TJ Sport and the key trick does not work on it. I went to Auto Zone and they pulled codes for me. BTW, key trick works on my 2000 WJ.

Yeah... That will Only work on '97 TJ's and the newer YJ's... Go to autozone.

Yeah... That will Only work on '97 TJ's and the newer YJ's...
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Sorry was in a hurry there... The Key trick only works on model year 1997 TJ's. It will also work on YJ's 1992 and after (thru 95).

Seeing as the TJ in question is a 1998, in my opinion, the best and least expensive solution is to go to auto zone to get the code read for free, or but an OBD II for lots of money.

Does that clear up the confusion?

Well, I have read that for 98+ jeeps, you could just hold the odometer reset button and turn the key to on. I tried it and have not seen any codes appear on the odometer, just a test of the dash functions.

The motor is idling rough, and it seems that it's just about to die, and there's a high pitch hissing sound coming from the throttle body. I think it might be the TPS?

I disconnected the battery, erased the code and everything was fine after that, no more codes and the engine is idling again like normal. wtf?

You have an air leak....