I have a 98, 4.0 auto. Hopped in today and all of a sudden it jerks while shifting, acting like the transmission is slipping. I have never had an issue before today. It threw an engine code and showed the transmission control module.

I was looking at my transmission and there is a small plug that is not plugged in, its on the driver side of the tranny. when I try to plug it back it, it wont go all the way in. Could this plug be connected to the TCM?

Any info would be greatly appreciated. I was trying to sell my xj today so it really sucked that its acting up. lost the sale.

 

Speed sensor plugs are on that side and they'll raise heck with shifting. Might have to clean the plug if there's road grime packed in there.

 

would that trigger the TCM code?

 

Exactly what code (number) did it show?

 

couldn't tell you. I had it run at the auto parts store. They showed me the results, it said transmission control module, I didn't write down the actual code though.

 

Well, fix up the plug and see what happens. Might also check the connectors at the TCU itself (under dash, passenger side). Make sure it has good power and ground.
Also the TPS can foul up your shifting pretty good when it goes.

 

Yeah I replaced the tps a few weeks ago. I'm not sure the plug is a speed sensor. Its at the end of the transmission near the drive line. the plug technically faces up towards the cab. It is a two wire, black and red.

 

Edit: nm, i had the wrong wire color for your year.

 

I think its plugged into the transfer case actually

 

Ah. There's a 2-pin connector for the dash indicators and a three-pin for the vehicle speed sensor that drives the speedometer.

Is it red/black and black, or red/black and yellow/black? Those are the usual dash indicator harness colors.