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aw4 help!! no reverse, no neutral,feels like its loading in park???

So i have this wiring diagram, referring to the nss as a gear selector switch.
the reason i believe they are one in the same is it has a starter relay out and a back up light out,along with the trans fuse connection, and it inputs to C8 and C9.
So, being that im getting constant power with the 1-2 gear and drive inputs,I think by running new wires to the tcu from the nss will solve my problem.
ill have to double check a few things before i get into it, but does it sound like im on the right track?
 
Red90Laredo said:
is the NSS good for sure?? I would double check that sucker before I ran new wires/
Click to expand...
it tested fine but ill re-test.
its just weird because i get .75 volts on C8 and C9 even with the NSS unplugged.
which makes me think that its shorting ever so slightly AFTER the nss harness.
 
It really does sound like a NSS problem though.
except the C8 and C9 showing voltage.
only when the tcu is plugged in though. then the only ones showing voltage are D14 D16
and then D14 when ign is off.
but plug in the tcu, and now there is input voltage on C8,C9, about .75 volts.
I didnt even pic it up on the analog voltmeter. i switched down to a lower voltage and then it showed.....
so i cant really believe i have 2 bad tcu's. so its something acting on the tcu to make it have .75 constant.
more tracing tomorrow.
any new ideas/suggestions with this info?
 
Here is a quick overall summary.
aw4 was not getting reverse, and neutral was a forward gear.


Checked TPS- Good
Checked NSS- Cracked and Damaged, Replaced
Changed TCU with a known functioning one- Functions identically to original
Checked Grounds- Good
Checked voltage inputs- Good
Checked all fuses-Good, nothing popped

Park functioned identically to reverse,which held the jeep in place and could not rev past two grand or so.
All other gears(1/2,3,D,N) felt like third gear, no matter what the selector was in.
Shift Solenoids #1 and #2 get constant voltage at the tcu outputs C15 and C16.

This happens even with the NSS and TPS unplugged.
Which leaves the speed sensor left to unplug.
Thats the only 3 inputs that would tell the solenoids to fire i believe,
and even with the key off, i measure around .1 volt on C4(diagnostic)
and .75 volts on C15 and C16.
Unplugged the TCU and ignition ON, and no more voltage to the C15 and C16, and only get voltage to D14 and D16 just as they should, ignition OFF and only D14 is hot just like it should be.
so maybe the speed sensor? or is my wiring FUBAR.
Ill check after i plow the annoying 2'' of snow in my driveway.



BTW got my NAXJA sticker today!!!:)
 
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Almost sounds like a wiring issue. the voltages to your solenoids are hot when key is OFF but they kind of switch around when key is ON.

Let me go check my C4, C15 and C16 for voltage.

Edit: No voltage for me. With TCM unplugged and Ignition OFF, do you read proper ohms at C14-16?
 
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I read 6 ohms at C14, and the other two are unplugged right now, so ill have to check that tomorrow.
but its supposed to be around 11-15 ohms, correct?
And what did yours read?
 
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Sorry I have been away... to answer your questions... The TCM takes gear selection inputs from the NSS for 3rd (D) and 1-2 only. All other gear posistions are selected in the trans it self. The defalt state of the Trans is S1 energized (open) and S2 non-energized (closed) and S3 non-energized (open, it's different the the others). This is how your trans should start and the shift to the next gear by changing the solinoed position.

So this is what I would try,
With your NSS un pluged. On the motor side I would put a jumper wire accross pins B and C. This will alow you to start the MJ. Then I would pull the jumper once it's running. This will give the TCM a "D" input. Put your MJ in reverse and see if it will back up. Then put it in drive and see if it will drive from 1st to OD. If it works then your problem is in the NSS. Another thing you could check is on the NSS it self...Pin G and H when you are in 3 or 1-2. If you have anything other the an OF or open then it's bad.... Good luck...:scottm:
 
I'll put the pan back on tonite or tomorrow and try that.
But here's something to chew on-

with the TCU plugged in, and NSS unplugged,Speed Sensor unplugged,brake switch and TPS sensor unplugged, and ignition OFF, I get .75 volts at D1,D2,D3
and .75 volts at C8,C9.
C15,C16 get .25 volts on the terminals on the TCU.

Unplugged the TCU and I only get voltage on D14 with the ignition off.
Fuse next to the TCU removed, i get the same voltages across the board with the tcu plugged in.
 
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Well the volts are not that high so the simplest answer would be your seeing ghost voltage. But you normaly won't see them in a DC setup... You said you had an extra TCU, I would plug that one in and do the same testing. If you get the same readings then it's eather normal or you have bad wires...
 
DownhomeMoto said:
Well the volts are not that high so the simplest answer would be your seeing ghost voltage. But you normaly won't see them in a DC setup... You said you had an extra TCU, I would plug that one in and do the same testing. If you get the same readings then it's eather normal or you have bad wires...
Click to expand...


I tried the other tcu, and its the same.
Bad wires inside both the tcu's?
because the only hot wire was the D14 when the TCU is unplugged and I checked at the harness.(ie solenoids ONLY get power when TCU is plugged IN)
there is something I must have overlooked, or not checked yet....:flamemad:
 
Will do.
So is that normal?
anyone with an AW4 that works want to take some simple readings at the TCU harness?
c'mon, you know you want to.......
 
any readings yet?
I put my tranny cover back in, filled it with fluid, left the tcu unplugged,plugged everything else in.
started it up, and same results.
Ill have to compare readings to rule out if the tranny is blown. So if you get to it, moto....
Thanks bro!!
 
im trying to figure out a solution for that too.
i may just use a rotary switch that can be set for two outputs.
ill explain more when i do more research, but it wiil work the same way as the skull shifter, just turning a knob, instead of a lever.
 
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