HDC Fault and Transmission Fault - 06 LR3 HSE - Land Rover Forums - Land Rover Enthusiast Forum

Go Back   Land Rover Forums - Land Rover Enthusiast Forum > Vehicle Line Up > LR3

LinkBack Thread Tools Search this Thread
Old 08-16-2012, 03:49 PM
Junior Member
Join Date: Oct 2010
Posts: 24
Thanks: 0
Thanked 0 Times in 0 Posts
Default HDC Fault and Transmission Fault - 06 LR3 HSE

I have a 2006 LR3 HSE that has recently been showing 2 faults at startup about half of the time and then they go off.

HDC Fault
Transmission Fault - Traction Reduced

Anyone know what could be causing this? I've read a lot of posts about weak batteries causing similar faults...
Reply With Quote
Old 08-17-2012, 06:11 PM
LR Techniker's Avatar
Senior Member
Join Date: Jun 2012
Location: Denver, NC
Posts: 263
Thanks: 0
Thanked 3 Times in 3 Posts

A weak battery can cause various faults, since data busses start to shut down below 10V. I would at least have your battery tested and if its OK, then I would have it scanned for fault codes before doing anything else. Without some direction (finding out what the vehicle is seeing) its basically a crapshoot.
Autohaus Lake Norman
7870 Commerce Dr
Denver, NC 28037
Specializing in Land Rover Repair
Authorized Bosch Service Center
Reply With Quote
Old 08-18-2012, 09:50 AM
bbyer's Avatar
Senior Member
Join Date: Sep 2008
Location: Edmonton Alberta Canada
Posts: 1,101
Thanked 58 Times in 54 Posts
Default odds are it is the brake light switch

Well it could be just a tail light bulb, but the odds are it is deterioration of the brake light switch - hence replace it. Also if you have installed any non LR spec tail and brake light bulbs, replace them even if they appear to be working with genuine.

Regarding the brake light switch, I have a theory that even if the switch appears to be working just fine, it is responsible for creating spurious signals that lead to the false error messages.

The set of contacts that is normally open operates the brake lights; the other set of contacts that is normally closed sends signals to the ABS module.

I theorize that dust from the deteriorating brake light set of contacts fouls the ABS contacts and leads to intermittent operation of the ABS contacts during normal driving particularly when one is not using the brakes. Since the ABS circuit communicates with the Hill Decent circuitry and that affects the transmission and engine controls, then anything is possible. For the most part, we are fortunate that all we get are false error messages and threatened system shut downs.

My reason for thinking the black dust causes problems with the second set of contacts is that that signal thru that set of contacts is closer to being a millivolt signal than the two or three amps of current powering the brake light filaments. In other words, the dust from the brake light contacts interferes with the flow of signal thru the ABS contacts.

As to why other vehicles do not seem to suffer this malady, well no other vehicle, (except maybe some Jeeps just recently), has a Hill Decent system.

Below is a link to a number of files related to the brake switch and changing it out.

DISCO3.CO.UK Photo Gallery - Brake Light Switch Replacement
2005 LR3 HSE; 4.4 litre AJ-V8 petrol; 18" wheels; Traxide Dual Battery install; PIAA 2500K H11 Yellow Ion Fog light bulbs; Rear Cargo area LED lighting; CounterAct LT-2 capacitive corrosion control device; LLumar AIR80 Blue Low E clear Infra Red heat reducing side window tint; Manual upper liftgate cable release; Schrader valve "air in" mod to OEM air tank; LR4 hitch receiver; Wiggs D4 Bluetooth module upgrade; 3 Blink signal light feature; Clock on the Dash; Backup Camera.
Reply With Quote
Old 08-18-2012, 11:26 AM
Join Date: Feb 2012
Posts: 48
Thanks: 0
Thanked 0 Times in 0 Posts

For me it was the battery. After I replaced it all the trouble alarms and warning went away.
Reply With Quote

Similar Threads
Thread Thread Starter Forum Replies Last Post
LR3 won't start, multiple codes and no solution. Trans fault Parking break fault, HDC mcvayrover LR3 101 01-16-2016 03:27 PM
2006 LR3 - Transmission fault, HDC fault, Parking brake fault, Engine system fault kbarker27 LR3 86 12-07-2014 08:39 PM
06 RRs, HDC Fault, Transmission Fault, Parking brake fault..etc etc 06Range General Tech Help 12 05-08-2013 10:01 PM
2006 LR3 V6 Suspension lowered, HDC Fault System not available, transmission fault Arth111 General Tech Help 4 03-13-2013 01:07 PM
LR3 Transmission fault, HDC failure and suspension lowered Aulmeck General Tech Help 10 07-29-2012 01:13 PM

2006, 2008, battery, brake, cleaning, fault, hdc, indicator, light, lr, lr3, range, rover, transmission, turn

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


All times are GMT -5. The time now is 03:40 AM.

LAND ROVER and its logo are the registered trademarks of Land Rover. Land Rover is not affiliated with LandRoverForums.com.