Hope someone can help. I am trying to locate the TCM on my 2006 XK8. Can anyone point me to the right location?
Thanks!

 

I think you'll have the 6HP26 in which case it's inside and oil-cooled.

It's rare to care - what are you trying to do?

 

Yea, as mentioned it is inside the transmission housing. You need to drain the fluid and remove the pan to access it and even then you can't do much unless you are planning on replacing the whole module.

 

That's what I was afraid of. I have the gearbox fault error and the car is in restrictive mode. I read where this could be a faulty TCM.
I am getting a P1642 code. Any ideas on what else to check?

 

P1642 is a CAN bus fault, the data network the ECM/INST/TCM/ABS share to pass messages. Perhaps a wiring issue would bear investigation before a module fault. Are you having any other codes from any other modules, and is this happening all the time, or intermittent?

Beyond this, I'd start at message #1 in the thread below
https://www.jaguarforums.com/forum/x...roblem-124765/

 

IF it really is the TCM and IF it cannot be reprogrammed I have one from a car with 52,000 miles on it with new solenoids.

pm me if interested.

 

There will be DTCs in the TCM.
Reading the ECM you got P1642 but you did not read the TCM.

 

Thanks for the replies! It is intermittent but I have noticed sluggish performance at lower gears. Sounds like I should check the wiring first I did replace the ABS unit about a year ago.
Dan

 

The TCM itself is very unlikely to be faulty.

As Bob said, read its codes.

If (a big if) the autobox has any faults they're much more likely to be due to low or old fluid or a worn item, but not the TCM.

 

I hooked up an icarsoft scanner to it and just got a connection error and could not read codes from any of the modules.
Any ideas?
Thanks!

 

Two of many possibilities
1. CAN bus is inoperative because of intermittent continuity problems on the bus noted by the P1642.
2. Scanner doesn't work well on your car.
...

 

First, check the fuse to the diagnostics port. If there is no power, the tool will not work. The tool should work at least over ISO9141 and give you ODBII diagnostics if there is power, even if CAN is not operational I believe. Next, you will have to do the basic CAN debugging by checking that 60 Ohms resistance. If not correct, you will have to start disconnecting modules one-by-one to see if it restores resistance. Keep in mind that the CAN bus is "terminated" by (2) 120 Ohms resistance, one in the ABS module, the other in the instrument cluster I believe. There is only a short list of devices on CAN anyway.

Are there any hints as to prior history that could explain any of this? Any repair, inspection, spills, etc. recently?

If you think the transmission is suspect, I would start with the data connector to the transmission in case the connector sleeve is leaking and causing the plug to fill up and fail. It is near/higher than the trans output flange, sort of dead center to the bottom of the car. A bit hard to reach, but doable on jack stands or ramps. There is a twist-lock mechanism that needs paid attention to (only the collar rotates, the plug absolutely cannot rotate). The seals to the sleeve fail "all the time" and are a known maintenance item. Pins in that plug also have a reputation for collapsing when messed with, so double check it. Just a thought.

Best of luck, keep us posted.

PS: do the lights on the shift surround light up and follow the shifter? This illumination is based on CAN...

 

To clarify, the diagnostics may or may not work, in general, depending on what's wrong with the network (i.e. shorts, or loss of continuity, or loss of termination should prevent function of the scanner), but if the whole network is fragged you should likely see the instrument panel (INST) complaining at the very least when you turn the the ignition on. Good suggestion on the fuses. The diagnosis of the termination does not rely on power, just connectivity or lack thereof between the diagnostic connector pins (ODBII connector) and the network/modules. If it's intermittent, there may be a period of jiggling wires to see which one(s) may be causing it...

 

ok, got it working. Cleared all the codes and took the readings. It now gives me a P1582 code.

 

I believe this is a ‘flight recorder code’, something that happened a while ago. Perhaps an inertia switch trip. But not necessarily indicative of a current issue.

 

On phone earlier, code description attached...

 

Just curious, what was the issue with the scanner, and did you get a glance at the codes that existed before you cleared?

Good luck with it.

 

The only way to clear the ECM data recorder is to go into SETUP and CONFIGURATION, Special Applications, Engine Data Recorder and CLEAR the data in both A and B sections.

The data will be cleared upon exit from the application if you choose Erase or Delete.(green tick/check mark) (no more P1582)

 

Ok - I cleared the codes and drove it around for 20 miles then it had a hard shift between 2nd and 3rd gear and threw a P0782 code. What do you think I should do next investigate the solenoid or have the fluid flushed and filled?
Thanks!
Dan

 

P0782 TRANS
OBD II

2–3 / 3–2 Gear load fault
Drive the vehicle at 113 km/h
(70 mph), then reduce the throttle angle until the torque convertor locks

Ensure that the torque convertor remains locked for at least 1 minute

TCM Default:
– Electronic limp home mode
— ECM Torque signal fault

Possible causes
Transmission mechanical failure