GanderThePanda

So I recently replaced my old leaky transmission with a used one off Facebook marketplace.

Now I have some new codes, P1694, P1698 and P0700. Jeep is running great, except it won't change gear until around 3000rpm from a stop. Very rarely it will go through a phase of changing into second around the 2200rpm mark, which sounds correct, from my time driving standard.

When I got this new transmission I had to splice every wire connection (including cps) to my old connectors. I don't know if the existing cps that was on the new Transmission was good, and I know it is possible that I may have damaged it during install.

Doing research, I've read that these codes usually accompany a bad TCM and a no start issue. I'm guessing that this may be a failing cps issue as these codes weren't present before (except P0700 from bad Torque Converter)? And my jeep starts and runs.

TLDR;
P1694, P1698, P0700
AW4 Changes gear at 3000rpm.Runs great otherwise. What are your guys thoughts before I throw $150 CAD on a new cps? Thanks!

BlueRidgeMark

None of those codes have anything to do with the CkPS. A failing CkPS will not set a code. You have no reason to suspect it has a problem.

ALL of those codes relate to communications between the transmission and the brains. You have a wiring problem. Possibly your splice work isn't good, or something similar. Maybe the P.O. yanked on the wiring harness when he removed the trans, and damages it. Something in the wiring.

Step 1: check your grounds. Why? Because that's always step one when electrical problems come up. See my sig, #1.

Pics of your splice might be good.

lawsoncl

First off, you need to confirm you swapped in a compatible year trans. Having to splice connections makes me wonder if you have an incompatible trans, as 98 was the year a few things changed https://www.naxja.org/forum/showthread.php?t=1053970

X2 on checking the wiring and fuse for the trans computer. Check the grounds, particularly the one at the dipstick. Test the throttle position sensor as the computer uses that and speed to determine when to shift. I assume you have the correct amount as Dexron in the trans, and the throttle-body -> trans cable is properly adjusted?

GanderThePanda

Thanks for the quick reply guys!

So as far as I know this is the correct year trans, I spent a lot of time trying to find a trans that would work. PO was lazy and instead of disconnecting connectors when he removed the trans, he just chopped the wires. So I spliced on connectors from my previous trans.

I'll get a pic of the splice work. Only thing I noticed that was different, was one or two wires had different colouring. Like I think the old trans had a drkblue with black tracer. The new one had ltblue with black tracer.

Cleaned all engine bay grounds a few months ago chasing a different problem.

GanderThePanda

Ok, so I'm not going to be able to look at my splices this morning as I need to drive somewhere later.

However, I did find a post on another forum about measuring your ccd bus voltages from the DTC.

I can report 2.42v on both the + and - circuits. This should indicate my bus line is good correct?

GanderThePanda

Here is the reason I was going to replace CPS.

lawsoncl

Ah. If they both had the front speed sensor on the drivers side up near where the bellhousing connects it should work. If the stuck one in that is missing that sensor, the rear speed sensor is the wrong type and it'll never upshift.

GanderThePanda

It will upshift, just most of the time not until 3000 rpms.
sometimes goes through phases of shifting correctly around 2200 rpms

BlueRidgeMark

Which leads me to wonder if he had done some yanking on that cable before he realized it was hung up, so at that point he just chopped them. Could be internal damage.



On the other hand.....


This part is a little scary. How did you decide which wires to match up?

Excellent.

GanderThePanda

All of the wires had the same colours and matched up except for two.
So the two odd pairs out were
1. the drkblue with black tracer paired with ltblue with black tracer.
2. White with black tracer paired with cream with black tracer.

Thing is, you wouldn't know there was something wrong unless you look at the codes.

Anyways.

I took the jeep out for a ride today and paid close attention to gear changes and the speedo.
I only counted 2 gear changes. 1 at 50km/h and the second at around 80 km/h at which point the TC locked up.

I'm wondering if this is caused by a bad shift solenoid for gear 2 (3000+ rpms to shift), Which would be a separate issue. (I believe I saw a code for a shift solenoid before, it just hasn't come back yet).

I'm starting to wonder if these codes p1694 and p1698 are being set by a weak signal from my splice job... As the jeep seems to work fine otherwise.