This morning I was driving to work and my Cherokee felt off to me and I couldn't tell why. Got onto the highway and it felt like something was off with the transmission like it was only partly going into gear and was having inconsistent power. Almost like a mild bucking is how I'd describe it. Shortly after that the check engine light came on and I quickly turned around and went home. Felt perfectly normal at low speed. Just connected my scan tool and it's showing a P1698 code which seems to be an issue with the transmission control module? I'm going to keep doing some research but I thought in the meantime if anybody has had this issue before and knows something that might help fix it, maybe they could lend some insight. This XJ is my DD so any advice in helping my resolve this is greatly appreciated. Thanks in advance!

 

Update for anyone who might be reading this at some point:

This is on a 97 Cherokee which I've read has a TCM that is unique to that model year and that the P1698 is a squirrely one. I removed the TCM and noticed a little bit of corrosion on the side of it. Opened it up and didn't see any corrosion on the board or anything that looked off. I've also read that it's a good idea to check your grounds with this problem so I replaced my badly frayed ground from the head to the firewall and cleaned grounds 102 and 103 by the alternator. You can see a picture of those in this thread:

https://www.cherokeeforum.com/f2/cha...oblems-227051/

Got everything back together and the code popped back up immediately so that didn't help at all. Did a quick test drive around the block anyway and tested reverse which didn't shift as hard as it used to so cleaning that one ground may have helped that like it did for the guy in that link I shared so that's good at least. I've ordered a re-manufactured TCM online and I'm hoping that will be the fix. Regardless, I'll update my post with my results.

 

That ground on the firewall to the head does almost nothing. it is there only for radio noise suppression.

The most important grounds are the main battery to block ground, and the battery to fenderwell. Of course, all ground connections are important.

Do a search here on TCM and you'll find plenty of reading about it. I have not had this particular problem, so I can't offer any other help on it.

 

Remove and clean these. Thanks goes to CCken for the pics.

 

 

Before you start getting all crazy replacing everything under the sun
Start here: check the TCM fuse under the dash:


Then, check that the battery has a standing no load voltage of at least 12.6 VdC
which should increase to ~13.8 VdC when the engine is running.

 

I figured it was insignificant based off one of the comments in that thread I linked. Oh well, it didn't hurt anything to replace it anyway. I've read a couple of posts about this issue but none have matched my exact problem that I've found yet.

I'll have to check out all of these grounds. Only cleaned two so far. Thanks for the help!

I've seen this mentioned. I'll have to look into that as well. TPS = Throttle Position Sensor? Thanks!

Is that under the passenger side of the dash? I went looking for it quickly behind the glove box and couldn't find it. My scan tool registers almost exactly these numbers for the voltages or should I break out the multimeter to be sure? Thanks!

 

Thanks again to everyone for the replies! So quick update: I replaced the TCM with a reman one and took a quick test drive and the code popped back up in less than a minute. I cleared the code and took another test drive pretty much just to see it happen again. I was further into my second drive when the check gauges light came on this time, followed by the Check Engine light. My voltage gauge dropped down to 9 volts so now I'm thinking this is an alternator problem perhaps. I replaced my alternator with a cheap one from Advance Auto about a year ago because I had no choice at the time. Some of the other threads about this that I've read have mentioned that replacing the alternator fixed their issue. Anybody else think this could be cause by the alternator?

 

If your voltage is flaky, all kinds of strange things can happen.

NAPA carries a good alternator with a lifetime warranty.

A code reader that can log everything that is going on is a nice thing to have for things like this. I like my OBDLink. The software is far better than Torque.

 

I ordered a new ACDelco alternator from Rock Auto. It can't hurt and even if it doesn't fix my problem, at least I won't have to worry about it for awhile.

I have an OBDLink. It sounds like I just haven't learned how to use it to its full potential.

 

Stick it in there and get it logging! It's amazing what you can see.

I have not tried the PC software yet, but if you have a laptop, you might want to give that a go. Take drive while logging.

 

Final Update: Replaced the crappy Carquest alternator (which had completely died) with a new Acdelco one and everything seems fine. Got about 50 miles on the Jeep since I replaced it and the code has yet to come back and it's shifting buttery smooth. So my advice to anyone who might read this in the future is to avoid the cheap remanufactured alternators from Advance Auto and by a better one if you have the option. Thanks again to everyone for all the helpful advice!

 

Thanks for getting back to us!