Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
Transmission Fault - Limited Gears Available / No Start
My LR3 nearly stranded itself yesterday.
Got a dash fault when driving on a gravel road yesterday, “Transmission Fault - Limited Gears Available”. I stopped the car to run diagnostics with GAP IID tool, and 4 modules repeated the same code and would not clear: “Lost communication with Transmission Control Module - Bus signal/message failure - missing a message”. Modules were Parking Brake, Suspension, Terrain Response, Transfer Case. With these codes present, the car would not start and shift lever would not leave P. This is the ZF 6HP26 Automatic trans, by the way.
After some fuss (jiggling shifter, cycling ignition between Pos I/II/III, and attempting to clear codes), I was able to clear the codes and start the car. We made it 100 yards before the codes returned. At the next stop, I was unable to restart the vehicle again and did the following:
Reseating mechatronix/transmission control module loom* —no change.
New brake light switch — no change.
4x4 Info screen showed vehicle in Neutral when it was in Park. Inspecting the shift linkage*, I found it was not loose or binding. Using the shift linkage bypass to put the vehicle into Neutral allowed the shifter to begin working again, and I was able to start the car and drive normally, with no dash lights.
I drove the vehicle 15 miles out on forest road, another 60 miles on the highway, and cycled the ignition 5-6 times as we stopped along the way. No issues. The vehicle drove beautifully on the way home and shifted wonderfully on the interstate, even in stop and go traffic.
*4 weeks/1000 miles ago I did a full transmission service. New filter, fluid, and valve body seals (requires dropping the valve body/transmission control module). I reused the old mechatronix sleeve because the new one would not fully seat. Removal of the transmission heat shield frame requires removal of the shift linkage.
Was this a fluke, or should I be looking into replacement of something? Is there a gear position sensor? Adjusting the shifter linkage? It seems odd that my linkage calibration could be out and only cause a problem now after working fine for 1000 miles.
Obviously goes without saying this is relegated to city driving until I confirm this won’t be an issue again. I’d hate to strand my family in the woods while on vacation.
Thank you in advance for any thoughts!
2008 LR3 HSE, 4.4L V8
18th Sep 2022 11:48 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10360
Try a small amount of city driving in off road height to provoke.
I’d be inspecting can wires which are yellow twisted pairs of wires.
Start at rear left of car
19th Sep 2022 7:24 am
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
Thanks, Pete. Issue was at normal height in highway mode, but I’ll try to provoke it by driving it every which way!
I was so focused on this being an internal issue with the transmission that I ignored the other communication faults that had cleared:
U0132-87 Lost Communication with ride level control module
*U0159-87 Lost Communication with parking assist control module
*B1B48-01 Rear Left Outer sensor - General Electrical failure
*These parking module faults have been around for a few months but they actually stopped recently. I thought they were nuisance faults, however they certainly seem related now.2008 LR3 HSE, 4.4L V8
19th Sep 2022 3:04 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10360
It’s not uncommon to get these loss of comm error codes on a good car.
Only you can determine if they occur at the same time as the car won’t move
19th Sep 2022 4:10 pm
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
Good point. Given the parking aid is on the medium speed CAN bus and it’s not caused serious issue, it’s probably a red herring. The Ride Level/Air Suspension comm loss is peculiar given the only module having issues reading it was the instrument cluster. I’ll keep note of this, but will focus on the others.
Based on Pete’s suggestion of High Speed CAN, I’ve found this highlighted bit of wiring is the common point between the TCM and all the modules that were not receiving its signal, so I suspect it’s another good place to start.
Click image to enlarge
Could anyone help chase down the routing of the wiring between the Transmission to SJ721/SJ1721/SJ2721/SJ6721 (SJ = splice joint?) and from there to connector C2365/C2366? I’ve found that C2365 is likely in the engine bay, along the fire wall, perhaps below the battery.2008 LR3 HSE, 4.4L V8
19th Sep 2022 7:18 pm
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
Per Pete K and this TSB, I checked the connector at the rear left of the vehicle (requires removing the spare tire). This had no chaffing.
I checked connector 2365/2366, which is under the battery. This area was dry as a bone. I did find some wires which were pulled tight against a metal hanger in this spot. They weren’t chaffed at all, but probably would have eventually, so that was at least worthwhile to find.
I confirmed the vehicle started in neutral as well as park, so it appears that the shift linkage calibration is OK. Test drive showed no faults. Only fault I got was the nuisance fault for the Parking Control Module, which runs on a separate bus network (medium speed) versus the high speed CAN that the drivetrain uses.
I am convinced at this point that the TCM plug wiggled loose on the few miles of gravel road, and it was stuck in park because the gear selector and position switch were out of sync due to lack of communication. Bypassing the shift lever and starting the car allowed the TCM to start talking to the network again, and all was right with the world. 2008 LR3 HSE, 4.4L V8
25th Sep 2022 7:23 pm
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
Well it happened again. This time 110 miles from home on the interstate. Same faults as before, all Lost Comms with Transmission Control Module. Happened on a smooth road at 65 mph so the loose plug seems less likely. At this point it’s also done 200 miles since the last failure. Also seems that the gear selector is fine.
Codes wouldn’t clear with car on or off. Car would not start with codes present. No live data from the transmission with codes present (See below).
Disconnected the battery for 10 minutes and car started. Once car started, I cleared the codes and could resume my drive. Made it 3 miles before faults again. This time I was driving with the GAP tool running, watching the live data. All streams were showing “OK” and then switched to “N/A” when fault tripped.
No shop availability at multiple shops until December, so I’m going to have to continue working on this myself.
Ideas are TCCM is failing, tccm connector is bad, bad wiring in the HS CAN network, bad plug elsewhere. Any thoughts on diagnostics to narrow my search?2008 LR3 HSE, 4.4L V8
7th Oct 2022 5:53 am
loanrangie
Member Since: 18 Jun 2017
Location: Melbourne
Posts: 599
What is the mechatronic sleeve like, any leaks in that area ?
7th Oct 2022 6:59 am
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
No external leaks. Here is a photo of the plug after I pulled it to reseat the first time. There was a bit of ATF on the bottom of the connector. This is internal the trans and ahead of the seal, so I presume it’s normal.
2008 LR3 HSE, 4.4L V8
7th Oct 2022 1:19 pm
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
Problem found!
Pin #14 in the connector plug got pushed in. This is one of two grounding wires, so it makes sense why the fault was intermittent.
Any thoughts on how to reseat the pin?
2008 LR3 HSE, 4.4L V8
8th Oct 2022 5:06 pm
MDOL
Member Since: 11 Jul 2023
Location: Donegal
Posts: 4
Hi, I have a 2007 HSE 2.7 Auto, only bought it last week and it need's some work, and it has a similar fault, won't start in P but will in N.
I think I will check out this pplug, where is it located?
11th Jul 2023 8:42 pm
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
Plug is on back of the transmission. Your problem is more likely with the linkage calibration or shift linkage bushing, look up how to calibrate.2008 LR3 HSE, 4.4L V8
11th Jul 2023 8:56 pm
MDOL
Member Since: 11 Jul 2023
Location: Donegal
Posts: 4
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