I've been chasing the dreaded christmas tree dash fault recently and every time I think I'm close or have sorted it seems to come back... I have a 2005 HSE.
The faults are ABS, Suspension and Special Programs. I have been having the "HDC Unavailable" fault on start up also.
I have already exhausted every thread I could find on the subject!
The fault is random and clears on a restart of the car. But when it occurs it deactivates all special programs and drops the suspension. Sometimes I can drive 28 Miles with no faults. Today I barely made it off my drive.
It would appear the fault is becoming more frequent now.
When I code scan the car - it seems indicate the Brake Light Switch. However; all the brake lights work and prior to the fault occurring (after clearing the DTCs) the Cruise works fine too.
So far I have:
- Changed the brake switch - twice
- I have changed the brake lights for genuine bulbs.
- Pulled the (admittedly wet) passenger side sill up to see if it's a fault with the 3 red cable splice.
- Checked Fuse F30
Now, I can't find the 3 cables in the passenger side. I have looked thoroughly. I'll check again for good measure when I have time.
- I have also checked the battery from cold (Left overnight) - 11.97V
- I have also checked the alternator after start up - 14.86V
Neither of those values seemed off to me - but I'm willing to be told otherwise. I had discounted a battery fault since the issue is so random. The car has never failed to start on me.
Things I haven't checked yet:
- TCCM; apparently the connectors can corrode; but I'd suspect other issues if that were the case.
- A different battery - Ideally I'd like to avoid buying a new one, especially if it doesn't sort it.
Can any of you clever people think of something I might have overlooked?
7th Nov 2019 4:21 pm
Littlewill
Member Since: 14 Sep 2015
Location: Lincolnshire
Posts: 484
Hi there,
Had this exact same issue with a D3 - It was the steering angle sensor that needed to be re calibrated. Really simple and really quick to fix it just needs re calibrating with an IID tool or similar. If you don't have a IID tool take it to Hunters Land Rover (near Sainsburys in Lynn)
Battery is really worth checking. Had a load of similar faults flash up on D4 one cold morning last winter. From what I could find at the time it was just battery volts dropped very low. 10 mins down the road, all was good again..
Dean
====================================
2011 D4 XS - OBD port protection, RLD spare wheel protector, All LED interiors lights, Timed Climate enabled, iiD tool paired.
2011 D4 Landmark - Stolen from same dealer before I paid for it
2011 D4 GS - Stolen whilst at dealer ... All LED interiors lights, DRLs, Spare Wheel protector.
1996 300Tdi - Eaten by tin worms
7th Nov 2019 4:39 pm
Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1782
There are 3 RED wires in the same loom that are also spliced. These relate to the brake light switch.
The 3-way Join to the left of the green arrow on the attached snippet. SJ1667.
Click image to enlarge
Last edited by Rockdrummerc on 8th Nov 2019 8:47 am. Edited 1 time in total
8th Nov 2019 8:44 am
Sea Raider
Member Since: 01 Nov 2016
Location: None
Posts: 4450
What scanner are you using and what are the codes shown?
Member Since: 01 Nov 2016
Location: None
Posts: 4450
I had an intermittent fault along those lines a few years ago
eventually traced to one of the ABS wheel speed sensors
When the sensor worked it cleared the fault so nothing was logged
Live values on the IID solved the problem.
Don't know if you can do live values with the Icar
this was mine
8th Nov 2019 8:51 am
MorganD379
Member Since: 29 Sep 2016
Location: SA62 3PP
Posts: 425
I have also had a similar problem, which turned out to be one of the rear hight wires had rubbed completely through... Was a pain until it completely went through.
8th Nov 2019 10:19 am
mattm
Member Since: 13 Apr 2014
Location: Aberdeenshire
Posts: 122
This is interesting, I have had almost the exact same issue the past four years running. Only happens over winter when it has been below 0 over night... after about 15 miles Bong! It used to do it without fail at exactly the same place within say a few hundred yards.
Year 1... Found battery terminals were lose.
Year 2... fixed it with a new battery
Year 3... New battery didn't fix it... change speed sensors, solenoid valves, a front height sensor and eventually new compressor seemed to cure it,
Year 4.... (today), bong, same thing all over again, Really getting to the end of my rope with it.
Ill check some of those wires this weekend and report back as it may help the OP if we both find some common causes.
Today I've changed the battery, removed the TCCM connectors and coated them in contact cleaner. I've also had a fan heater on the pulled up carpet to dry the footwell out (2kW Paint heater).
None of these have helped, I managed 600 Yards before the fault occurred again. I wondered if it was possible that the battery needed a charge, but I checked it out of the box and it was reading 12.46V; which I thought would be acceptable.
However - I decided to drill down with the iCarSoft and check to see if it was the ABS sensors or Ride height sensors. I threw up the Data Monitors and took it for a few short drives around the industrial estate I work on, keeping an eye on the screen.
10 minutes of driving - no lights, no sign of anything unusual on the readouts. Checked various modules and sensors too.
Then once I'd stopped and parked back up, thought I'd have a look at the Brake Switch; since that is the thing that keeps coming up on the scanner.
I sat there for a bit pressing the pedal up and down; watching the indicators on the screen flit between "Active" and "Inactive".
I noticed that the two were slightly out of sync; that makes sense, there's two different switch contactors in there... So this got me thinking; I wonder if it's possible to get into a position where one is in the "Active" position and one is "Inactive".
So feathered my foot around a little and came close a few times, eventually came to pretty much my rest position....
They held in opposite states - BONG - all the lights come on; suspension drops.
So... I've cracked it...
Now - is it possible to adjust the pedal? Or have I screwed myself over by just buying a cheap switch?
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... All LED interiors lights, DRLs, Spare Wheel protector.
