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Transmission Fault: HDC, Traction Control off, etc.
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bjwhite
 


Member Since: 17 Aug 2011
Location: Seattle, WA
Posts: 24

United States 2006 LR3 4.4 V8 HSE Auto Chawton WhiteLR3
Transmission Fault: HDC, Traction Control off, etc.

I know, I know. Brake light switch right? Not in this case.
I've been through many things to try and track this down, but now that winter is among us, I really need to fix it as the traction control is inoperable with this fault.

The symptom is this.... If I put my foot on the brake and start the car everything seems fine. However, if I remove my foot from the brake I immediately get a transmission fault along with Traction Control light on and amber BRAKE light (North American LR3). Using my IIDtool that code is U0416-86 (2F) Invalid Data from Vehicle Dynamics control module.

Upon further inspection I also get "P0504-64 (2A) Brake Switch A/B correlation" and "P0504-29 (2A) Brake Switch A/B correlation" which also makes it seem brake switch related.

I have two brake switches as I had replaced the original one due to normal maintenance and keep the original one in the vehicle just incase. Both switches behave the exact same way.

BUT HERE IS THE KICKER--which I think is the root of the problem. If I use the IIDtool to go to Live Values, I can go to the brake light switch operation under the Transmission menu. If I leave my foot on the pedal, the brake LIGHT switch function says ON and the brake switch function says ON. If I remove my foot the brake LIGHT switch function goes OFF and the brake switch function stays ON and this is when I get the transmission fault with no HDC, TC light, etc.

What boggles my mind is where to go next.

One little issue I noticed was during last winter, I was driving on a mountain pass on some rainy roads. Taking a high speed left hand turn, the TC kicked on just for a little bit. I thought to myself, "Wow, must be slippery out here." But later on, even as spring arrived and it was not as wet outside, on certain left hand turns, the TC would kick on--even when it was dry. Soon thereafter, this fault started and has remained throughout the summer.

I find that an odd occurrence...given the symptoms that happened just after this.

So...I've come to...bad or damaged wiring somewhere? Or...is this a symptom of the "Bosch Transfer Case ECU" behind the battery? I did check that and while I saw a tiny bit of evidence of wetness or water at the connector, the inside of the ECU box was as pristine as new and dry as a bone.

Anyway....have any additional thoughts? I'm going out to check 12v at the red wire at the brake switch....and is there anything else I can glean from my IIDtool?
  
Post #156571622nd Nov 2015 10:44 pm
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bjwhite
 


Member Since: 17 Aug 2011
Location: Seattle, WA
Posts: 24

United States 2006 LR3 4.4 V8 HSE Auto Chawton WhiteLR3

Can a mod move this to the D3 forum? I accidently posted to D4..
  
Post #156574323rd Nov 2015 1:09 am
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ajps72
 


Member Since: 01 Sep 2013
Location: Lima, Peru
Posts: 20

2013 Discovery 4 3.0 TDV6 Base 7 Seat Auto Barolo BlackDiscovery 4

the awitch has 2 contacts, so it can still be one of them.

if you have washed the engine bay behind the battery, then I will think about the offroad module
  
Post #156574423rd Nov 2015 2:01 am
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sean 471
 


Member Since: 26 Apr 2011
Location: Sheffield
Posts: 2691

United Kingdom 2007 Discovery 3 TDV6 Pursuit LE Auto Java BlackDiscovery 3

I have had the same after changing several brake switches. Make sure it's fully engaged Thumbs Up
  
Post #156575523rd Nov 2015 7:36 am
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bjwhite
 


Member Since: 17 Aug 2011
Location: Seattle, WA
Posts: 24

United States 2006 LR3 4.4 V8 HSE Auto Chawton WhiteLR3

Also, can anyone confirm that I should be getting 12v at the red wire on the brake switch connctor? In this case I do not. Hmmmm..
  
Post #156597723rd Nov 2015 2:44 pm
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Robbie
 


Member Since: 05 Feb 2006
Location: Waiting for my old avatar to be allowed back... we miss her!
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United Kingdom 2013 Discovery 4 3.0 SDV6 HSE Auto Baltic BlueDiscovery 4

Yes, you should have 12v on the red wire. If you do not then that circuit has failed, probably due to a split or corroded splice. Run a wire with 12v on it to the switch and see if all your problem disappear.

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 Land Rover - Turning Drivers into Mechanics Since 1948

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Post #156597923rd Nov 2015 2:51 pm
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bjwhite
 


Member Since: 17 Aug 2011
Location: Seattle, WA
Posts: 24

United States 2006 LR3 4.4 V8 HSE Auto Chawton WhiteLR3

Thanks Robbie. Anyone know where this red wire goes? Where is the nearest splice? I assume under the side rails under the black plastic trim along the doors. Left side or right?

I did have quite a lot of water intrusion last winter due to a dry rotted sunroof drain in the left side footwell (driver's side in my case)
  
Post #156598323rd Nov 2015 3:03 pm
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Robbie
 


Member Since: 05 Feb 2006
Location: Waiting for my old avatar to be allowed back... we miss her!
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United Kingdom 2013 Discovery 4 3.0 SDV6 HSE Auto Baltic BlueDiscovery 4

It's not worth your time and effort to find and repair the splice. Just grab some +12v loveliness from a suitable source at the base of the a-pillar and run a new wire to the switch.

After all, there is plenty beer in the world that needs drinking.

Thumbs Up
 Land Rover - Turning Drivers into Mechanics Since 1948

Battery & Quiescent Current Drain Testing

Diagnostics for:
Defender, FL2, D3, D4, Evoque, RRS & FFRR
A not-for-profit enterprise


 
 
Post #156598623rd Nov 2015 3:06 pm
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Martin
Site Admin and Owner 


Member Since: 06 Nov 2004
Location: Hook Norton
Posts: 16865

Wales 2006 Discovery 3 TDV6 SE Manual Buckingham BlueDiscovery 3

The red wire and the green with orange wire should both have 12V when the ignition is switched on.

The red wire is switched to the purple with green and goes off to the ABS/TC module.

The green with orange is switched to the green with purple (yes, really, the opposite of the above) to the lamps.

As your brake lights work, you presumably have 12V at the green/orange, so you can bridge across to restore the supply to the second (ABS/TC) function.

The red 12V supply comes courtesy of Fuse 66 (5 Amp) in the dash fuse box, and feeds the DSC switch, the HDC switch and the steering angle sensor. It is worth checking this fuse is OK as there is more involved than just the second brake switch circuit.
 06 D3 SE / 15 LR D90 XS SW / 88 LR 90 Td5 / 68 BMW 2000 ti
Any issues with the site let me know! 
 
Post #156599023rd Nov 2015 3:22 pm
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bjwhite
 


Member Since: 17 Aug 2011
Location: Seattle, WA
Posts: 24

United States 2006 LR3 4.4 V8 HSE Auto Chawton WhiteLR3

Thanks Martin (and Robbie).

Interesting you say what you say about the system. Because while holding down my brake pedal and doing some testing this morning, I realized that my HDC was completely dead trying to control it with the button.

However, the fuse 66 is intact just fine--as well when I start it with my foot on the brake (before the Brake switch A and B correlation causes the errors), I can properly operate the DSC switch. Also, using live values with the IIDtool I can "test" the steering angle sensor and all looks good.

So that proves at least part of the circuit is operational. Lastly, I did a double check of the brake switch connector. Testing the brake lamp side (the green with orange) I get 12v there with the ignition on. This is why my brake lights actually work--as previously mentioned. But testing the red wire, I get nothing.

This is awesome progress actually! It gives me a path of troubleshooting. I'm going to at least see if I can trace it and repair whatever connection is damaged, corroded or broken all the while having the "run a new 12v source" as a backup.

I'm looking forward to actually fixing this. Thanks everyone for your input. I'll report back.
  
Post #156624823rd Nov 2015 8:37 pm
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Martin
Site Admin and Owner 


Member Since: 06 Nov 2004
Location: Hook Norton
Posts: 16865

Wales 2006 Discovery 3 TDV6 SE Manual Buckingham BlueDiscovery 3

OK here is the relevant bit from the circuit diagrams.

I admit this is for a RHD car but I am hoping NAS is the same or similar enough to make sense. Embarassed

The arrows and extra labels are my additions.

Click image to enlarge


You are looking for a break in the circuit somewhere to the "left" of the green arrow, as all functions to the right of it work.

The C1165/C1167 connector pair are the green 22 way plug/socket at the bottom of the right hand A pillar, behind the trim.
 06 D3 SE / 15 LR D90 XS SW / 88 LR 90 Td5 / 68 BMW 2000 ti
Any issues with the site let me know! 
 
Post #156628023rd Nov 2015 9:03 pm
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bjwhite
 


Member Since: 17 Aug 2011
Location: Seattle, WA
Posts: 24

United States 2006 LR3 4.4 V8 HSE Auto Chawton WhiteLR3

Martin, this is brilliant and I thank you very much for your help.
I finally had a chance to track a bit more of this down and I had a follow up question.


Looking at the connector C1165/C1167 I do get 12v at the red wire going into that connector--so the break must be after that connector (to the left). Which brings me to my question. Is SJ1667 a splice somewhere? It sure seems like it to me---and if so, it makes me wonder if this splice is under the left side (driver's in my case) floor wiring path along the footwell. Remember, this footwell was full of water for quite some time and if so, a cheapie splice as LR used in these would be easily damaged.

Also, if anyone can answer--does the HDC button light up at all with night illumination? I can't remember.
Thanks again--I'm making progress....hopefully to locate this splice and repair it.
  
Post #15749639th Dec 2015 6:44 pm
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bjwhite
 


Member Since: 17 Aug 2011
Location: Seattle, WA
Posts: 24

United States 2006 LR3 4.4 V8 HSE Auto Chawton WhiteLR3

Success! I located the bad splice and while I haven't fully repaired it, I did jump it with some leads and did some testing and everything works as it should.

Thank you Martin for setting me upon the correct course--realizing that the 12v at the red wire in the brake light switch harness was key--along with the "half-operation" of things on that circuit.

The splice in question was in fact SJ1667, which is located on the right side front door (NAS LR3)....in the sill where the mass of wires is located, just before the turn upwards going to the grounds and higher up, the fuse box.

One red wire coming from the back of the vehicle, going into two red wires from the front in that sill area. They were taped with light blue electrical tape and the connection was completely severed--lots of green corrosion in what was left of that connection.

I am going to repair this with crimped butt connectors and waterproof heat shrink. All in all a completely easy fix that was a pain to track down. Thank you again Martin.
Brian
  
Post #157678313th Dec 2015 5:37 am
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Robbie
 


Member Since: 05 Feb 2006
Location: Waiting for my old avatar to be allowed back... we miss her!
Posts: 17537

United Kingdom 2013 Discovery 4 3.0 SDV6 HSE Auto Baltic BlueDiscovery 4

Thumbs Up
 Land Rover - Turning Drivers into Mechanics Since 1948

Battery & Quiescent Current Drain Testing

Diagnostics for:
Defender, FL2, D3, D4, Evoque, RRS & FFRR
A not-for-profit enterprise


 
 
Post #157698913th Dec 2015 3:55 pm
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Martin
Site Admin and Owner 


Member Since: 06 Nov 2004
Location: Hook Norton
Posts: 16865

Wales 2006 Discovery 3 TDV6 SE Manual Buckingham BlueDiscovery 3

Excellent, always good to hear success stories Mr. Green Thumbs Up
 06 D3 SE / 15 LR D90 XS SW / 88 LR 90 Td5 / 68 BMW 2000 ti
Any issues with the site let me know! 
 
Post #157701513th Dec 2015 5:20 pm
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