aw4 only manual shift

[llhat]

I've searched and found prior issues but not exactly... and yep this is a long arsed post...

 

1989 Comanche 168k 4.0 renix (stock)

some time ago, transmission started not shifting, and not taking off in 1st gear (sluggish start).  I use vehicle sparingly and just placed shifter to 1 and manually shifted, and also noting no converter lock up.

Some other issues got in the way and now started diagnostics using the tips posted elsewhere.

 

Have found some other info online.. one is here https://itsajeepworld.com/wp-content/uploads/2019/11/auto-trans-diagnosis.pdf

but of course do not have the scan tool!

 

So far:

Removed lower dash panel to  better access fuse panel and TCU

 

Checked, inspected the 7.5 trans fuse in fuse panel ( back probe with 12v test light to ground, both sides of fuse, OK)  removed and checked continuity OK

 

Checked, inspected the 10 trans fuse in the in-line holder ( back probe with 12v test light to ground, both sides of fuse, OK)  removed and checked continuity OK

 

Under hood,  found the gray connector and separated,  could see 'nothing wrong' with internal connections

 

so, first question...  the connector side with MALE pins,  can you confirm it is From the TCU or is it to Transmission?

a FSM diagram shows male pins from TCU and female to the transmission

 

I used an on-line manual reference above and found this diagram to identify the pin-outs.

7way.pdf

 

the line of 3 pins,  center pin is B,  I checked continuity between this pin and negative battery terminal  .4 ohms, so that is reaching ground.

I tried probing between this same pin and others,  no continuity to any

 

So proceeded to female side

 

7way female.pdf

 

 

used probe to check from middle pin on 3 row to battery....  no connection.

 

I also probed to what should be the transmission solenoids looking for 12-13 ohm range...   Get open circuits.

actually same as the male side,  no continuity to any cavity to B

 

I was HOPING to find an open SOL 1 before i dive into the transmission internal connections... but with nothing, at an impasse

 

What i have YET to do is probe from Center female on 3 row to Engine/Transmission body...  thinking maybe internal ground connection in transmission.

 

any assistance appreciated... and what am i overlooking?

 

I have not tried plugging everything back up and test shift/ take off.

 

 

 

 

 

 

[Ωhm]

10 hours ago, llhat said:

so, first question...  the connector side with MALE pins,  can you confirm it is From the TCU or is it to Transmission?

a FSM diagram shows male pins from TCU and female to the transmission

 

 The question here is do male pins go to Transmission or do they go to Engine Control Harness. I can't tell from the photos, but one side goes down to the trans.

 

 

 

10 hours ago, llhat said:

the line of 3 pins,  center pin is B,  I checked continuity between this pin and negative battery terminal  .4 ohms, so that is reaching ground.

I tried probing between this same pin and others,  no continuity to any

 

I think you're talking about the male pin side of the connector. If true, this side goes to the Engine Control Harness.

 

 

More Info:

_mj1988electricalmanual_1.pdf

[llhat]

thank you for the response.

i have a hard copy of the manual you attached.

so confirming

Male pin side of C114  goes to TCU, not the transmission.

Pin B is the ground and there's continuity to the negative battery terminal.

 

Female side of C114.

Probing mating of pin B  and any of the solenoid female cavities  I get nothing...  that is the present confusion.

 

Solenoids 1, 2 and 3 ground to the internal body of the transmission...   

 

so, next will be a test of female cavity b to engine/transmission ?

 

I also have found in other manual a through-connector to transmission body, I think near flywheel on passenger side.

 

One now has to believe the harness is bad...  which is strange in itself  (scratching my head)

 

I'm now guessing a pan drop is in order and probing the connector from s1, s2, s3 to the female side of C114

 

What would be of course helpful would be the cavity on the diagnostic port  (which one)  and could it be probed to see

if +12v is being sent to solenoid from the TCU

 

sure would like to get it fixed,  tired of shifting manually.

[Ωhm]

 

 

50 minutes ago, llhat said:

Female side of C114.

Probing mating of pin B  and any of the solenoid female cavities  I get nothing...  that is the present confusion.

 

Should read the solenoids if all testing was done on the same side of the connector.

 

 

 

52 minutes ago, llhat said:

I'm now guessing a pan drop is in order and probing the connector from s1, s2, s3 to the female side of C114

 

Tough call here. Seems to be the next step.

 

 

54 minutes ago, llhat said:

What would be of course helpful would be the cavity on the diagnostic port  (which one)  and could it be probed to see

if +12v is being sent to solenoid from the TCU

 

Best you can do here is check for voltage at the TCU.

C234_D14 - Hot at all times - (D1_5)

C234_D16 - IGN SW Run/Start - (D2_4)

 

     

[llhat]

thanks for that and an 'update'

yesterday i modified the pins on a cheep multimeter so they would insert into the female side of c114

(thinking not getting connection was reason for not being able to test solenoid windings at the connector)

 

no change.

Found in some info there's a thru-connector on transmission for the wiring to penetrate the transmission case.

 

I was going to raise vehicle on my lift to check this out, but experienced a hydraulic line failure....  *&%$&  ...  pretty much too old

to crawl around on floor,   so this will be on back burner... moving on to other tasks on MJ...

 

I know i have power to TCU... and as a hail mary yesterday I removed 'cover' from TCU to examine board for any obvious blown resistors or caps...

nuttin

 

Out of all this,  it is leading me to a harness failure... which to me is 'strange'...   but certainly murphy's law prevails.  can't see how it would just fail

 

again, thanks for those pin-outs...    Is there  a method on the  D1/ D2 for testing of signal "to" the solenoids?

 

 

[Crash]

If you really need to drive it you can shift manually. I'd maybe see I'd you could get another TCM to try. 

[llhat]

thanks,  i have been driving/ manually shifting.

 

about to the point of investigating again, have some other tasks to handle.

 

I am still perplexed that I cannot get a solenoid reading through the connector..   and when i get my lift fixed I will just drop the transmission pan and get some long leads to test from connector terminal to the solenoid connector.

 

I found in giggle search the part number for the solenoid harness, but of course long discontinued....

 

not even seeing anything for used ones out there.

 

I will also confirm 12v at the tcm connection.

 

I have a new NSS, but do not think that is anywhere near the issue.

 

grasping for straws.