Member Since: 06 Mar 2017
Location: Lost
Posts: 4805
Yes.
Peeps get confused between Transmission Control Module (auto only) and Transfer Case Module which both manual and auto have. yµ (idµ - eAµ) ψ=mψ
1st Jun 2024 6:26 pm
sailingaway
Member Since: 10 Dec 2015
Location: Hampshire
Posts: 89
Super thanks. I’ll check that in a moment.
I’ve taken the old speed sensor rear right out, and there was a bit of dry rusty particulate on the magnet. I’ve wiped that off, but my question is should there be any grease/lubricant in there? Couldn’t get a photo as foolishly I wiped the particulate off on autopilot.
New sensor just arrived so I’m about to fit that and if it doesn’t solve the problem try and figure out access to the TCM and other connectors.
Click image to enlarge
2nd Jun 2024 11:57 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4805
No there's no lubricant required and the pick-up should only ever be cleaned with a brass wire brush, never a steel one!
You can apply a smear of copper grease to the retaining bolt thread as sometimes they can seize with rust. yµ (idµ - eAµ) ψ=mψ
2nd Jun 2024 1:47 pm
sailingaway
Member Since: 10 Dec 2015
Location: Hampshire
Posts: 89
Click image to enlarge
Copy that - thanks!
New sensor fitted and the problem persists. All looks well at the TCM (to my untrained eye) so I'm going to check out the wiring in the footwells; unclear whether that should be left or right side but I'll hope to find them.
Click image to enlarge
Click image to enlarge
2nd Jun 2024 1:53 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4805
If after a new sensor has been fitted and the problem persists the likely culprit will be a failed cable in the block connectors on the N/S chassis rail behind the strut.
You need to clean them off (wd40/white spirit on a rag) and examine them very carefully for chaffing, chips, or breaks. Any exposed copper will appear as a green spot on the wires so cut and splice or bridge the damaged areas.
Opening the blocks will likely require a suspension recalibration on reassembly, though not always. In any case it's a doddle with IID and the "guided calibration" method. yµ (idµ - eAµ) ψ=mψ
2nd Jun 2024 3:57 pm
sailingaway
Member Since: 10 Dec 2015
Location: Hampshire
Posts: 89
Your assistance knows no bounds and is much appreciated.
Between my last post and checking back I’ve pulled up the gutters in the car and it looks like someone may have had a go at some wires before. Connection looks ok however, but I intend to remake it with a waterproof connector.
Click image to enlarge
I also took the near side (left) front wheel arch apart and found 3x block connectors - are these the ones you’re talking about? If so, any tips on getting them apart?
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If not, are you talking behind the rear wheel (and I will reassemble front and move to rear!).
Thanks
2nd Jun 2024 5:48 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4805
The green wire inside the sill cover is the splice for the central locking which someone has done a bodge to. It should be soldered or crimped properly and sealed.
On the N/S/F wheel arch connectors check carefully the wires for corrosion (green spots) or other damage. The plugs pull apart once you press the tangs but are tight. You could use a DMM to check the voltages/resistance either side of the connectors to see if the values are the same. I think the white or WY is the one you're looking for but I'll attach the wiring diagram at the bottom of this post.
If you find a fault too close to the connector just splice in a new bridge and bypass the connector for that wire/s. If no progress then move on to the rear blocks as mentioned earlier.
Member Since: 10 Dec 2015
Location: Hampshire
Posts: 89
PROFSR G wrote:
The green wire inside the sill cover is the splice for the central locking which someone has done a bodge to. It should be soldered or crimped properly and sealed.
Great, thanks, I've re-made that connection and it's much neater.
I couldn't see anything obvious on the N/S/F blocks (and couldn't get them apart although I did clean them) so I have moved to the N/S/R blocks. Getting into what I think is the blocks was a bit of a challenge as the plastic shield was a pain to remove, and everything looked very dry, muddy, and dusty in there!
Click image to enlarge
I've started looking at the wires, but it would help if I could remove the blocks from their mounting, and get them apart. Can't readily figure out how to do that but I'm working on it.
Click image to enlarge
Not sure how best to go about using my DMM to trace the fault - assume I would measure the resistance across the WY and W for the rear left for example (known good) and compare to the resistance across the WG and W for the rear right, working back until I get a good resistance, and this would tell me where the fault was?
(I've also found some more interesting 'features' on the left hand side passenger footwell - there's some blue tape which I think is covering some terminated wires, but short of cutting the cable tie in there I can't really get in to see what's been modified and why)
Click image to enlarge
3rd Jun 2024 3:50 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4805
I'd suggest you clean thoroughly the wiring to the rear blocks first and see if there's anything apparent. Alternatively, if that's not working for you just pull the lock levers and separate the blocks. You will perhaps then be better able to examine very closely for damage. yµ (idµ - eAµ) ψ=mψ
3rd Jun 2024 8:22 pm
sailingaway
Member Since: 10 Dec 2015
Location: Hampshire
Posts: 89
I'm in the process of admitting defeat I think. I've chased as much wiring as I can and can't find anything obvious. I thought I was on to something with the rear right as I found the sensor wire coming sideways out of the plastic protection, but a thorough inspection doesn't show any damage obvious there.
I have been unable to separate any connectors. Just can't figure out how to pull the lock levers, and I don't want to break anything.
Member Since: 10 Dec 2015
Location: Hampshire
Posts: 89
Great thanks. It's booked in with them for July (the sign of a good garage is when they're booked up!) so hopefully they'll sort it .
4th Jun 2024 4:25 pm
sailingaway
Member Since: 10 Dec 2015
Location: Hampshire
Posts: 89
The plot thickens for me.
I went back to the N/S/R connector blocks, and re-checked them finding they had nothing to do with the speed sensors. I then went back to basics and headed over to the O/S/R wheel, testing the resistance on the sensor there, followed by the resistance on the connector blocks (which I finally got open!) behind the N/S/F wheel. Finally I checked the resistance on the pins at the ABS unit itself under the bonnet.
In all cases the resistance was either just above 6 ohms or just above 8 ohms depending on which way round the multimeter was. This matched the resistance of the N/S/R wheel sensor. As far as I can tell this proves that the wiring between the sender and the ABS unit does not have a short. This would suggest to me that the issue may be with the ABS unit itself?!
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