Hi everyone, I am a professional automobile technician and i recently acquired a 2004 x- type 3.0 awd. A couple days ago I was driving in the rain and the vehicle went in to limp mode and would not shift out of first gear. Checked for codes and its throwing a p1710 and p0743. I am going through the diagnostic procedure for p1710 and i have some confusion regarding connector jb155. I am trying to test the ground between the connector and the TCM and ive noticed a couple inconsistencies between the electrical diagram in the service manual vs what im actually looking at on the car. the service manual says that pin 18 on jb155 is the ground to TCM and should have a black wire. Looking at the car the wire coming off of pin 18 is green and not black and there is continuity between that and the ground, it is way higher than the spec. showing around 6kohm and should be 5 or less. when i try to check continuity from that pin to pin 17 on the TCM connector im getting an open circuit. something else confusing about the diagram is, it shows pins 1-10 as being the row on top and 11-20 as being the pins in the bottom row, but the connector on the car only has 18 pins. This has me questioning whether not i am testing the correct pins. Per the service manual, i tried to check continuity between pins 17 and 18 on jb155 on the transmission side and I got around 6 ohms, which according to the book, indicated a faulty torque converter lock up solenoid, but again i am questioning whether or not i am testing the correct pins. I have read about water getting into the TCM and causing problems as well. I pulled the TCM out and opened the case and did find water damage on the board. I cleaned it up with a q tip and rubbing alcohol, and have not yet retested, as i want to ensure the rest of the circuit is good before trying it. if anyone has an ACCURATE pinout diagram of jb155 or any other insight into this issue, i would greatly appreciate it, thanks

 

I did go ahead and reinstall the TCM and as i expected, no change

 

Does your TCM have a single 37 pin Blue connector (16 Bit TCM) or does it have two connectors totaling 42 pins (32 Bit TCM)?
2004 is a tricky year of production as they implemented a number of changes to running gear and modules during that year.
I'd suggest starting tracing the earth from the TCM side by first figuring out which plug/pin from TCM and what wire colour at that end first.
If it is a single Blue 37 pin plug then you are looking at confirming ground on pin 17 (Black solid wire).
If you have a 32 bit TCM with two 24 way plugs then you are looking at pin 4 on the white plug which should still be a black wire.
No variants I can find have an occupied 20 way connector at the transmission, all have an 18 way black connector.

As far as corrosion goes on and int he TCM, the scupper drain holes get clogged and then water can enter the cabin air filter intake under the front windscreen cowl which finds its way through the heater onto the cabin loom that tracks down to the TCM on the A pillar.
Clean the mild corrosion growth off IPA or Methylated Spirits and reseal the board with a lacquer if necessary. Clear the drain holes at each side of the scupper and you will probably be good.

Friendly note: Wiper arms can be a b!tch to remove if you are removing cowl to access filter, use a good wiper arm puller as they will likely be corroded on.

 

its the 16 bit TCM. I have not confirmed pin 17 on the TCM is ground, but i will do that. Attached is the image I am using as a reference, I found it in another thread on this board. Its 100% an 18 pin plug, but the thing that's confusing to me is how they are numbered on the diagram. The top row is numbered 1-10 and the bottom row is 11-20, so I'm looking for some clarification on that.

This car sat out side for about 3 years before i started driving it and there are a ton of leaves up under the cowl. On top of that, it had been raining heavily all day it broke down while driving in heavy rain, so I suspect the wet TCM is the root cause. I am tempted to throw a TCC solenoid at it and see if it helps, but I'd really like to diag it properly before cracking open the transmission.

 

I would suggest you look at the wire colours going into the end pins of each row. 3 out of 4 should be black and one should be brown.
The brown should be pin 10 at the beginning of the second row.
That should orientate you.
I think the 20 way connector image you have is a red herring.

 

I dont think we are talking about the same connector. I am talking about jb155 which is the big plug on the outside on the transmission that connects the shift solenoids to the TCM. the P0743 code i have is for the TCC solenoid circuit and the p1719 is for the control valve solenoid ground. I am trying to verify that the ground on that plug is good and check the solenoids to make sure they are ok and i need to know the pinout of the big plug on top of the transmission. I have the pinout for the tcm and will be able to verify the wiring between the transmission and TCM is good once i have this pinout. I want to be able to confirm if i have a solenoid issue, a tcm issue, wiring issue or some combination of the three. included are pictures of the plug in referring to.

 

I believe we are....JB155 circled in red and the respective colours I was referring to circled in green for pins 1, 9 ,10 and 18.

I quickly checked 2003, 2004 and 2005 schematics and wire colours did not change for these pins.

Doe the wires change colours across the male to female ends of that plug assembly?
Your lower two photos seem to have the black and brown wires the schematic refers to......

 

ok i think i understand now. 10 is brown and 18 is black, so the row that starts brown and ends black has the ground on the ending black wire. the other row is pins 1-9. it looks like some of the wires do change color across the plug. from here i think i can make my own diagram to help me. its probably going to be at least a week before i can get back to testing this thing, but once i do I will post the results. Thank you for your help

 

ok update time.
Did some testing this morning and here are the results.

I checked for continuity on the TCC solenoid across pins 17 and 18 of JB155 and got a reading of 11.7 ohms and the spec is 12-13.3 ohms. It is a little out of spec but not by enough to convince me its the issue. I then checked continuity between pin 18 of jb155 and the battery ground. I got a reading of about 10.9 kOhms which is way high, spec is 5 ohms or less. In order to rule out faulty wiring, I checked for continuity between pin 18 of jb155 and pin 17 of jb131 and got a good reading, very little resistance. then just for fun a verified i had a good ground between pins 9 and 38 and battery ground and again had a good reading with very little resistance.

To me, this condemns the TCM as the rest of the circuit seems to be in working order. The TCM did have signs of water damage so it checks out, at least in my mind. I made my own pinout diagram for jb155 and it helped immensely. I will up load here and make a better version if anyone is interested. I am on my way to the salvage yard to hopefully pick up a TCM. I'm not sure if it will be an exact match, or it could also have water damage, but i figure its at least worth checking out. I will continue to post updates as i make progress

 

salvage yard TCM was the correct part number but had more water damage than the one i already have

 

Do and online check to see if Auto Reserve in the UK have anything in there salvage stock currently.
Alternatively if you want to stay within US available parts, try reaching out to the forum member Dr Dome, who does have X-Types he is breaking down and may have a TCM available.

 

Quick question, will a used tcm need to be programed? ive seen mixed answers online. most say absolutely yes, others will say that it doesn't need it as long as the part numbers are close enough. Who would i go to for that if my local jaguar dealership cant or wont do it?

 

been a while, but im finally getting back to working on this thing. I have my replacement TCM and before i install it, i want to make sure the drains in the cowl are clear. any pointers on a good way to do that? I have my cowl off and there is a bunch on dirt/debris in there, but in not sure which holes need cleared out

 

I believe the drain holes are in the outer corners of the recessed cowl area which just have a gap that drains down into the fenders behind the plastic inner wheel arch liners.
Common issue of the drain holes being blocked with debris and holding water within the cowl that then finds its way into the cabin air intake to dampen your carpets and track along wiring to the TCM.