I have a 2002 TJ Magna Wagon 3.5Ltr Auto. It keeps on going into " LIMP MODE ". I have changed the computer,de-coder,ignition barrel & key, etc but i still have the same problem. Can anyone please please help me.

Wrong section btw - this should be in the 3rd gen tech section. Hopefully mods will move it.

Now for your problem - not sure why you're changing the ecu, immobilser, key barrel etc when you've got a limp mode problem which is related to your gearbox?

Maybe you should get the car inspected by a transmission specialist since it's a transmission problem? I can't understand why would you replace electronic parts when the problem originates from the gearbox. If you don't replace/fix the gearbox then how is a new ecu/bem/keypack etc going to stop the car from going into Limp mode? The problem hasn't been rectified.

I suspect you're probably up for a new gearbox as something has killed it.There's about 3 main things that can kill the magna gearboxes - wave spring failure, planetary gear failure or the oil pump bearing. Either way needs to be inspected by a pro.

I'd advise to budget for a replacement or a rebuild.
If you need a gearbox quickly and not concerned about warranty or any assurance then head off your local wrecker and pick a 4sp auto off a TH-TJ as it'll bolt up and plug in. If possible inspect the oil to make sure its pink however most wreckers drain the oil from the car.
If you want more asssurance then speak to Mal from Mitsfix (Madmagna) as he offers warranty.
Otherwise the best thing would be to have the box completely stripped down and rebuilt using a new revised wave spring and oil pump bearing. It will cost at least 2k to do but the gearbox will probably outlast the car.

Wrong section btw - this should be in the 3rd gen tech section. Hopefully mods will move it.

Now for your problem - not sure why you're changing the ecu, immobilser, key barrel etc when you've got a limp mode problem which is related to your gearbox?

Maybe you should get the car inspected by a transmission specialist since it's a transmission problem? I can't understand why would you replace electronic parts when the problem originates from the gearbox. If you don't replace/fix the gearbox then how is a new ecu/bem/keypack etc going to stop the car from going into Limp mode? The problem hasn't been rectified.

I suspect you're probably up for a new gearbox as something has killed it.There's about 3 main things that can kill the magna gearboxes - wave spring failure, planetary gear failure or the oil pump bearing. Either way needs to be inspected by a pro.

I'd advise to budget for a replacement or a rebuild.
If you need a gearbox quickly and not concerned about warranty or any assurance then head off your local wrecker and pick a 4sp auto off a TH-TJ as it'll bolt up and plug in. If possible inspect the oil to make sure its pink however most wreckers drain the oil from the car.
If you want more asssurance then speak to Mal from Mitsfix (Madmagna) as he offers warranty.
Otherwise the best thing would be to have the box completely stripped down and rebuilt using a new revised wave spring and oil pump bearing. It will cost at least 2k to do but the gearbox will probably outlast the car.

Ummm because most of the time a limp mode issue is from the TCU which is part of the ECU and requires a BEM and KEY to be REPLACED with it unless you know how to recode stuff like I do....

Generally the issue will be with the TCU or the TCU plug due to coolant or faulty ECU but before you go in and start replacing this stort of stuff you really should see what is issue is first.

Could be as simple as a dirty plug on the trans, could be the solonoids in the trans have stopped working, damaged engine loom. If you are stumped is now time to get checked properly as the suggestions I have listed are pretty much the main causes. Most trans issues will not be picked up by the TCU so will not bring up codes etc