Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
That’s really helpful, thank you.
Just looked under the truck (it’s a 2005) and can’t see an earth strap from the transfer case to the chassis, and I seem to recall seeing a picture that this is maybe only on 2007 onwards? If so, are there other earth straps you think might be worth looking for?
Thanks again by the way.
31st Dec 2023 12:50 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4664
No you're correct, I forgot yours is an early car and it was not fitted to the early models. The other main earths are the battery obviously, and one located in the drivers side wheel arch behind the cover which goes to the engine mounting on the drivers side.
I doubt these are the cause or you'd have bigger issues like starting/charging/battery drain etc! You could for the hell of it try a jump lead or even two of them. One from the box to the body, and one from the engine to the body and see it anything changes?
There are around another 30 or more minor ground points distributed around the vehicle. I don't want to send you on a wild goose chase, but some of them can be seen in the engine bay inside the where the wings mount. See the map below.
Click image to enlarge
yµ (idµ - eAµ) ψ=mψ
31st Dec 2023 4:26 pm
oxtobyd
Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
Update: got a used gearbox wiring loom and swapped that in (getting the bl**dy xy sensor plug off/on was a pain, literally), and….. no joy!
So I’ve swapped the gearbox loom, the TCM module has been checked and no signs of corrosion anywhere, I also a while back swapped in a replacement TCM (using SDD to code it to the truck). I can now only assume it’s an earth problem but when I look at live data I can see the values for X and Y positions do change. So I’m confused.
I’ll check earth straps on off-side front wheel inner arch.
4th Jan 2024 10:11 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4664
I know, the XY lead is awkward to put it mildly, but you got there.
Do another sweep of the codes (include all modules) and post them here, but this time include the coms faults ("U" codes)
If it's an earthing problem you can help circumvent this with jump leads strategically placed on the transmission to body, and engine to body!
Did you try a test drive?yµ (idµ - eAµ) ψ=mψ
4th Jan 2024 10:21 pm
oxtobyd
Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
Update #2
So… got the multimeter out before wiring in some earth straps to see if they would be needed. And I could measure across the batter 12.4v, and then from the Battery - to the chassis 12.4v, from the battery - to the engine 12.4v, and you guessed it from the battery - to the Transfer Case 12.4v. Which makes me think all the grounds are ok? And also tried with engine running and same reading of about 14.5v at all points
Also, here’s the full list of fault codes from last read (below) any ideas? Thx
RLM
U0416-86 invalid data received from vehicle dynamics control module
ATCM
U0416-94 invalid data received from vehicle dynamics control module
TCCM
P174C-00 Gearshift lever Y position sensor - circuit low
P1807-00 Four-wheel drive high ratio - short circuit to ground
VDM
U0128-87 lost communication with parking brake control module
BCM
B1B02-28 low frequency coil
B1C57-14 Unused relay drive
HVAC
B1B78-84
System pressure
6th Jan 2024 2:42 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4664
Given where you are now after the loom replacement, earth tests etc, no hard EPB fault, and the fact that you can see the XY actually shifting would lead me to look closer at P1807-00.
Could be an issue with this motor, the plug pins, or the switch pack itself? I'd be leaning towards the switch pack in the first instance! Remove it from the console and check it carefully, you can use electrical contact cleaner to get down into it. If anything spilled onto it like a soft drink it would gum up the contacts inside as it dried out. Blow out any cleaner and dry it before refitting, especially if you use brake cleaner. Whilst it's good at loosening and dispersing any crud it will short the electrics if not dried out thoroughly!!
If that doesn't help move on to the motor.
Most of the "U" codes are what I'd expect to see given the fault. The others I do not think are relevant.yµ (idµ - eAµ) ψ=mψ
6th Jan 2024 3:35 pm
oxtobyd
Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
Update:
Been delayed doing anything due to work & family, anyway….
Thought I’d clean all fuses and swap out TCCM with a known good, and not a lot of difference other than I’ve lost the P1807 code, and left with what’s below. So stumped, unless faulty wiring somewhere else, any suggestions where to check?
RLM
U0416-86 invalid data received from vehicle dynamics control module
ATCM
U0416-94 invalid data received from vehicle dynamics control module
TCCM
P174C-00 Gearshift lever Y position sensor - circuit low
VDM
U0128-87 lost communication with parking brake control module
BCM
B1B02-28 low frequency coil
B1C57-14 Unused relay drive
HVAC
B1B78-84
System pressure
14th Jan 2024 1:49 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4664
Did you look at the switch pack?yµ (idµ - eAµ) ψ=mψ
14th Jan 2024 4:18 pm
oxtobyd
Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
I did, it looked good as far as I can see, but couldn’t take apart very far, ie could see bottom of circuit and all clean, but not the top as couldn’t get into the unit further without of breaking the case.
14th Jan 2024 5:17 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4664
You have to ask to where or why did P1807 disappear?
What did you do that deleted that code? (short to ground)
When you replaced the loom did that include the TCM plug?yµ (idµ - eAµ) ψ=mψ
14th Jan 2024 6:53 pm
oxtobyd
Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
Good question, I removed the swapped in harness as it was only Jerry-rigged in place to test, and as made no difference then removed, so back on original harness, so may have just been thru the replugging in and cleaning contacts that has fixed the high/low error. Or when I explored the switch pack may also have resolved that, even though I didn’t do anything with it really.
Thinking I try a replacement switch pack and see how that goes?
14th Jan 2024 6:59 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4664
Hmm, I'd be looking again at the contacts in the TCM plug as something has improved it's grounding to delete P1807. Switch pack swap is no harm if only to rule it out.yµ (idµ - eAµ) ψ=mψ
14th Jan 2024 7:44 pm
oxtobyd
Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
update:
so changed the switch pack, and sadly nothing, so have the following codes still
RLM
- U0416-86 invalid data received from vehicle dynamics control module
ATCM
- U0416-94 invalid data received from vehicle dynamics control module
TCCM
- P174D-00 Gearshift lever Y position sensor-circuit high
VDM
- C1A00-88 Control module
- U0128-87 lost communication with parking brake control module
BCM & HVAC
I'm ignoring as I don't think relevant
I'm wondering if there's a bad ground on the ABS module causing all the VDM errors?
I've re-checked the contacts on the TCM module, and they look fine and the plug ends all look good, and as noted already changed the gearbox loom, but of course there's the other two plugs and their wiring that come out of the module, but from what I can see all look ok at first glanse.
Wonder if bad ABS ground would also throw a TCM (XY Switch sensor error)? since that VDM error messages are a bit hit and miss.
16th Jan 2024 4:30 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4664
There's always the risk of overthinking these issues so for now I'd be doubtful there's an earth issue with the VDM. Stay with the simple stuff, change the brake light switch and /or the handbrake switch and see what that brings.
Cheap and quick if it works, which it often does!! yµ (idµ - eAµ) ψ=mψ
16th Jan 2024 4:50 pm
oxtobyd
Member Since: 21 Feb 2023
Location: Lincolnshire
Posts: 24
Many thanks, i changed the brake pedal switch early on in my ownership trying to track this problem down, but had just left the problem until recently, when I'm like a dog with a bone and want to get it sorted.
Anyway, I'll order a used park brake switch and see if that does it.
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