Auto M + S Error Code P0705 Position Switch Monitoring caused when underbody wet

[twr7cx]

Went offroading over the weekend and had a continual battle with the automatic transmissions M and S lights flashing on the dash when the underside of the vehicle was wet. The Nanocom advised automatic transmission error code P0705 Position Switch Monitoring and using the Nanocom to clear the error codes and WD40 over the sides of the transmission and all the connections for the wheel hub sensors the error would sometimes go away and allow me to progress (until water splashed up again). It worsened over the weekend and on Sunday I was unable to clear the error for a length of time.

Following reading previous threads I checked the ECU for any oil signs, none, and then removed the XYZ/Inhibitor switch. Opening up the switch and it looks dry and clean inside - no signs of water. Any other ideas on what could be being effected by the water to cause this error?

[strangy]

Harness from the Auto into the cab is known to chafe.
Also Id have a look at the Auto ECU under the seat and check plug and pins.

[Toppa]

I remember being told the loom that runs over the trans chafs as mentioned earlier. Being wet would help create the short whereby it may not otherwise when dry.

[sierrafery]

If it's caused by water concentrate on the plug first(shown in the bulletin), unplug it and give it electric contact spray or better naoprotech electric which is water repellent if you can buy it locally , see this http://landroverclubvi.weebly.com/uploads/2/3/9/8/2398536/sport_and_manual_mode_light_illuminated_860403nasf .pdf

[twr7cx]

Harness from the Auto into the cab is known to chafe.

Where is the common chafe location on the loom?Is it best to do a full removal as per


see this http://landroverclubvi.weebly.com/uploads/2/3/9/8/2398536/sport_and_manual_mode_light_illuminated_860403nasf .pdf

to visually check for the chafe? It's very limited visibility underneath the vehicle of it.

[Pedro_The_Swift]

There are pics of the loom/chafe area here,, somewhere...[bighmmm]

[twr7cx]

There are pics of the loom/chafe area here,, somewhere...[bighmmm]

As to where, I still cannot find them.

[twr7cx]

I pulled the XYZ switch off, opened it up and cleaned it out. It looked clean inside. There was one track which had some green on the copper. Cleaned it all up with electrical and circuit board cleaner. Dried it out. Tested all the tracks, wires and switches with a multimeter. All checked out in all the positions. I'm not convinced that this was my issue.

Going to try and get the USB endoscope up above the gearbox to check the wiring loom. There is no viability from under the car.

I notice that the TI linked above specifies:


WARRANTY CLAIMS: 86.70.20 ...................Time: 0.90 Hrs
Replace gearbox harness
44.15.19 ..................Time: 0.30 Hrs




Replace start inhibit/neutral safety switch

My understanding is to replace the gearbox harness you need to remove the centre console. LR are providing 0.90 Hrs (54 minutes) to complete this task? Seems way too short of time!

I feel that I should get in there and check the wiring loom but I can't see how to undo the other wiring connections which are onto of the automatic transmission and TC, plus disturbing it can also cause an issue if one doesn't already exist. If I recall when I removed the auto last time I accessed the wiring connections when it was lowered a bit.

[twr7cx]

A few notes for anyone reading this in the future.

Removing the centre console is not a hard job. Just followed Rave instructions but note what they don't tell you is that the automatic transmission shift knob takes a hard pull upwards to the remove and the transfer case knob unscrews.

If your thinking about changing the transfer case shifter and/or handbrake gators, hand time to do it.

The clevis pin for the handbrake is about the hardest part - getting it back in through the cable and lever.

The big note though is that before you go to the time and effort of removing the centre console, get under the car and starting from the rear of the gearbox/handbrake drum/transfer box, stick your hand up, find where the wiring looms comes through the bottom of the car and you should be able to feel all the way along it - I felt no chaff or damage to mine. Also using a cheap eBay endoscope with built in LED lighting helps to confirm.

[sniegy]

My D2 had this issue, The issue is where the loom comes from the vehicle down across the top of the T/case & it sits in a "Metal" P Clip.
That is where the issue lies. The harness is wrapped in a metal type of sheathing, But hard to detect in the sheathing until the loom is in your hand & you are feeling for & while looking at the loom.
HTH
Cheers

[twr7cx]

My D2 had this issue, The issue is where the loom comes from the vehicle down across the top of the T/case & it sits in a "Metal" P Clip.
That is where the issue lies. The harness is wrapped in a metal type of sheathing, But hard to detect in the sheathing until the loom is in your hand & you are feeling for & while looking at the loom.

Thanks for that. I decided to remove the centre console and the wiring loom to check. Glad I did follow through as it had rubbed through exactly where you said (where the metal P bracket secures the wiring loom):

https://www.aulro.com/afvb/images/imported/2017/07/518.jpg
https://www.aulro.com/afvb/images/imported/2017/07/519.jpg
https://www.aulro.com/afvb/images/imported/2017/07/520.jpg

Undoing the connections on the TC and auto transmission are not fun to get it out! For anyone else doing this in the future, check out Automatic transmission and transfer case wiring connectors - how to undo? (https://www.aulro.com/afvb/discovery-2-a/251500-automatic-transmission-transfer-case-wiring-connectors-how-undo.html) for some details to assist in disconnecting everything to remove the wiring loom...

[twr7cx]

A tip for anyone in the future doing this. You don't need to remove the centre console. just the power window/heated seats switch panel which is enough to give you access to the plugs for the transmission wiring loom.

[bgkdavis]

oh dear....... had the flashing M + S appear on my D2a today.... quickly zapped this with my nanocom, and hoping I never see it again [bigwhistle]

on the 'plus side', I know I have a dodgy battery terminal.... maybe I should get that fixed sooner than later!

[twr7cx]

While looking for the transfer case wiring colours today I realised that if you removed the plate at the top of the transmission tunnel you'd be able to disconnect and remove the wiring loom from the top down. Probably much easier to do. e.g.

diffspigot_fromabove_web.jpg (http://www.discovery2.co.uk/images/diffspigot_fromabove_web.jpg)



on the 'plus side', I know I have a dodgy battery terminal.... maybe I should get that fixed sooner than later!

From what I've read, issues with the battery connections or faulty batteries can be a cause.

[bgkdavis]

From what I've read, issues with the battery connections or faulty batteries can be a cause.

Yeah, that is what I've read too, so ill make that my first port of call for repair before I try ripping out the harness

[bgkdavis]

`had this reoccur today with fault P1843 CAN TIMEOUT MONITOR reset it agian!

[strangy]

Check oil in engine ECU plug and corrosion in EATECU (under pax seat)
The CAN bus wires are a twisted pair white yellow.

[Pedro_The_Swift]

added this to TGO,,
Thanks twr7cx,, [smilebigeye]