Tranny code question...

Hey guys, newbie here and new to jeeps. The forum is great and I've found most of my questions answered just by searching. Sorry for the lengthy question...

History: 98 Sport, 4.0, auto. 160K, Bought it used, drove it home @ 3 hrs with no problems and no CELs except it stalled in the last mile home. It needed some TLC and a minor tune and my girlfriend brought it to a "tech" friend to go through front to back (gift for her daughter). Picked it up after a few weeks, the guy had lots of trouble stalling/starting and turned out to be quite the parts changer and not too big on diagnostics. It still had the stalling issue, that I found through some digging here that was a bad wire going to the stator, but more troubling is that it's throwing out 0700 and 0705 codes with the check engine light on now. I fixed the stalling issue, cleared the codes with my reader but they are still coming back. He installed a new TCM and NSS (and a WHOLE bunch of other crap) and given the codes I'm thinking it's related. We had no shifting issues before, and still don't. The NSS is working fine, starts only in neutral and park, and I'm getting continuity between terminals 8 and 7 only in those gears on the connector, but the codes keep coming back (also an 1899 code that comes and goes, but sounds related).

I did clean all the grounds I could find in the engine compartment, and everything looks solid. Any thoughts on what could be tripping these codes still. I did read somewhere about having to drive it for some time before the codes would clear, and I've only driven it a few times @ 20 miles each. Also read something about a connector under the dash, but not too sure where to start there.

It's starting to drive me a bit nuts! I'd love some input.

Thanks!

• P0700 Transmission Control System Malfunction
• P0705 Transmission Range Sensor Circuit malfunction (PRNDL Input)

P1899, P0700, P0705 are all telling you there is a problem. P1899 and P0705 are telling you that there is a problem with input data FROM the NSS.

As Shade Tree Johnny's competence has been brought into question by you, and Shade Tree Johnny did something with the NSS, I would pull the NSS and see what was done. They need to be cleaned and lubricated, as well as installed and adjusted correctly to function properly.

Hey Joe,

He didn't take the time to clean the old NSS, he threw a new $280 one in for us. It does seem to be aligned based on what I read about how to do it, and seems to be working fine based on continuity testing of the connector. My best guess is bad connectors or something to that effect. I will say, I spent a few hours today chasing down all the other grounds to block and chassis I missed the other day and pulling connectors apart and coating with dialectric grease. I drove it home from my shop after posting and finishing the work. I cleared the codes before I left and the CEL didn't come back on on the half hour ride home (it would come on withing minutes of driving earlier). This car lived by the ocean, and I will say there was a fair amount of corrosion around the engine compartment. I'm crossing my fingers, but not holding much hope right now.

If it comes back on, I might ask for a new link or description on how to properly adjust the NSS. It seems pretty simple, and the continuity is dead on but maybe I missed something.

I'll update either way in a few days.

Thanks!

I was right not to hold out hope. Just ran out for dinner and the check engine light is back taunting me. I'll have to pull the code in the morning, but I'm guessing it's the 0700 & 0705 again.

Back to the original question then... new parts, seem to be working, still popping codes. Any thoughts?

Let's see what the codes say.

As for the NSS, unless they are physically broken, they can be cleaned, lubed, and adjusted. Unless yours was broken there should have been no need to replace it.

Might want to check and see if the "Tech" over-tightened it when mounting it.

Thanks Joe, I'll pull the codes shortly. Interesting thought about overtightening, he was very sloppy in everything else he did, why not that. As for the new part vs. cleaning, I'm guessing it's just laziness and my girlfriends money. There's a list of parts that he changed that seemed fine when we dropped it off, and you can almost follow the "diagnostic" path to a problem. The stalling issue I think resulted in a new ignition switch, starter (which he didn't charge us for, my guess is he burnt it out cranking!), and I thought maybe the NSS was in that path. I don't know why the TCM would be changed though, we didn't notice any shifting issues when we drove it home from Boston.

I'll post the codes shortly. Thanks

your first post leads me to believe there was no CEL until after your "tech" gave it back.

If this is the case, see if you can get the TCU that he pulled out of it. If it didn't have shifting problems, CEL codes, or NSS related problems until he "fixed" it, it's definitely possible that he either installed the incorrect TCU or managed to install one that was bad to replace yours that was still good.

I was thinking the same thing actually. There were no lights on before we brought it to him but we literally only had about 4 hours total drive time on it. My best guess is that all this is related to the parts he changed, but I can't figure out why he did. The broken wire to the stator might have led to the NSS change, but even then if the NSS wasn't working, the motor wouldn't even crank which wasn't the issue (crank but no start). Who knows?

I pulled the codes, the same 0700, 0705, and 1899. I'm checking to see if I can get the old parts back. Can anyone tell me where the TCM is located on my '98? I read it was under the passenger side dash, but couldn't find it. Maybe the description was for a different year.

I'm also going to pull the switch and open it up to see what I can find. Maybe he did overtighten it and it's a little caved in. Is the best was to adjust it after by using the continuity of the #7 & #8 pins?

although I've never actually looked for it, I believe I read somewhere that at some time they moved the TCU to the drivers side (just to the right of the steering column)

how's this scenario sound:

1. didn't crank for "tech"
2. changed starter
3. didn't crank for "tech"
4. changed NSS-- failed to adjust correctly
5. jumped starter and started
6. drove to verify it runs ok-- trips trans codes (incorrectly adjusted NSS)
7. "tech" re-adjusts NSS so it'll crank and pulls codes
8. replaces TCU ('cuz the codes say there's a problem)
9. new TCU is bad

Just a guess, but if it didn't give you any reason to suspect TCU problems before he touched it, it's one possible explanation...??...??

yep, 97 was the first year they moved it to the drivers side. It's a little box about 2" square.

Make sure yours reads 98M (may have a different letter) or has part number 5604 1386AA or 5604 1386AB. If it has a 5602 7951 in it, bring it back to him and tell him he's an idiot and owes you a TCU for the right year range, 98-01.

You need a new shadetree mechanic... I would volunteer but I am far too busy presently.

I matched the numbers on the TCU and it is the correct 386AA. I'm going to check the connector and add some dialectric grease. The girlfriend talked to him about getting the old parts back (he's a family friend which is how it ended up there in the first place~ and I'm not allowed to talk to him because she's correctly afraid I'll rip him a new one...) and he mentioned something about the TPS not getting 5 volts which if I understand her correctly led to the replacement. I'll pull the NSS off too now and see what I find...

The TPS is powered by the ECU, so if he thinks that correctly led him to the replacement of the TCU he's wrong. The TPS still could have needed replacing though, they tend to go bad once in a while.

Hey, quick question about testing the TPS. I'm assuming it's the sensor on the back side of the throttle body coming off the throttle plate (different from photos I found online) with a white connector. Could someone tell me which terminal is the ground, 5v power and variable? Thanks!

Information from the 97 FSM:

"THROTTLE POSITION SENSOR (TPS)
The TPS can be tested with a digital voltmeter. The center terminal of the TPS is the output terminal. With the ignition key in the ON position, check the TPS output voltage at the center terminal wire of the connector. Check this at idle (throttle plate closed) and at Wide Open Throttle (WOT). At idle, TPS output voltage should be greater than .26 volts but less than .95 volts. At wide open throttle, TPS output voltage must be less than 4.49 volts. The output voltage should increase gradually as the throttle plate is slowly opened from idle to WOT."

This just keeps getting better! Driving home late last night, motor just drops right off and stalls. I get it started again in neutral while coasting, then a minute later is does it again and won't restart in neutral. I throw it in park, and it starts right up again. Maybe coincidence? Stalled again on the way into work today. Now it starts in every gear, not just park and neutral. I pulled the codes, got the same 0700, 0705, and 1899, plus a p0351, which is the ignition coil circuit.

I haven't pulled the NSS out yet, but unless it totally failed from yesterday when I tested it I have to believe there's a deeper issue. Any new thoughts while I pull/test the NSS?

That it will start in any gear--NSS problem.

The NSS can't kill the motor, you have more than one thing going on.

Repair the NSS, then get on to the intermittent stalling.

No chance to get to the jeep today and I'm gone over the weekend. I'll update what I found next week. Thanks for all the help so far!

If you think you may need a part, shoot me a PM as I have a 97 in pieces right now.
If the parts dont work, just send them back and pay nothing. Shoot me a PM if need be.
Did you test the TPS yet? As I have had those do all kind of funky things, except outright stall a motor...
Martin

i have a 98 xj as well and battled these codes for some time. i had very similar problems\symptoms. it took me a few tries to get the nss adjusted for things to operate correctly. despite using a continuity tester, i still had to have another set of eyes on the reverse lights to make sure they came on when adjusting the nss. (put shifter in reverse and moved nss into position until reverse lights came on and car would start in N and P) do you have reverse lights when the cel is on? maybe adjust the nss to see what happens, its free and easy to do.

you mentioned in your posts that a total stoppage of the engine occurred while driving for a little while. maybe after the car is warmed up heat is playing a role here. my friends xj had a tps go bad. started to create problems similar to your stalling issues. seemed whenever his rig got up to temp issues followed soon after. after some diagnosis and a part replacement he was good to go.

x2 on the tps diagnosis joe put up.

Back in town and hopefully getting some time on the jeep today. I'm going to start by pulling the NSS and checking it out. It is brand new, but I didn't install it so who knows? Thanks yetimotronic, I'll try the reverse light method for adjusting afterwards. Thanks too Joe, I'll test the TPS today as well, although that is supposedly new too. The stalling issue does seem to pop up after warming up, but not consistently, and before we could definitely relate it to the bad wire to the stator which I've replaced and can't get to stall by wiggling it now. This new stalling just started and the 0351 code is new as well (as is the start in every gear mode it's in now). Can all be related to the NSS? That wouldn't kill the motor would it? What would trip the 0351 code? Anything I can track down there?



The problems seem so random sometimes I wonder about the PCM... any thoughts on that?

First some diagnostic work... I'll post results as I get them! Thanks everyone!