Disco 2 Hazard lights flashing

[Nchanga55]

Hello All,

My apologies for not posting in Dutch but im an Englishman with only three Dutch lessons under his belt....

I have a discovery 2 (2002 240000km) TD5 automatic with an electrical problem and wondered if anyone can help.

When the engine is running, after about 20 to 30 seconds the door locks automatically unlock and the indicators flash. The only way to clear the fault is to open the door, lock/unlock the car and restart the engine. We first noticed the fault after land rover had to clean the ECU from an oil leak. It was initially intermittent (could drive for three days without a problem then it would come back).

Land rover Romijn have so far replaced the following;

First the BCU(fault still there) and then the fuse panel underneath the steering column. They were 99% sure this would fix the fault but failed.
They have also disconnected the volumetric sensors and the inertia crash sensor but the fault comes back.
I have had the car for some time at land rover romijn but they are unable to fix the problem and have advised me to take it to their specialists in Best, however I have already paid allot of money for land rover to fix the fault and they have failed so I’m not prepared to spend more money.
Any help would be greatly appreciated. I live in Delft and don’t know of any independent dealers with testbook or nanocom.
Adversly, anybody who wants to take the car off my hands.....give me a shout.

Cheers,

Sean.

[Roger B.]

de inertia-switch kan dit soort gein geven inderdaad, en dat is er dan weer lastig uit te krijgen met contact en geen contact en knop indruken hield het op een gegeven moment op... maar dan zou het ook niet weer vanzelf terug moeten komen zonder de iniertia switch te activeren lijkt me.


The inertia switch can cause this kind of idiotic behavior indeed, and it's sometimes difficult to get it working correctly again, with ignition on and of and pressing the switch eventually it stopped... But it should not come back out of the blue without having activated the inertia switch....

[RobStewart]

Hi Sean,

The Inertia switch has 2 functions in the event of an accident, one to shut off the fuel pump and secondly to trigger the hazard warning lights and unlock the front doors. Now it is interesting in your case that the engine keeps running but the doors unlock and the hazard warning lights go off.

The inertia switch has a positive feed from Fuse 13 in the engine fuse box, this then supplies the switch through a Brown/Black wire, as the switch is normally closed the current flows on a White/Green wire back to the engine fuse box. This feed supplies the ECU and also main relay in the engine fuse box which in turn supplies both the starter relay and the fuel pump relay. Now we can assume from your description that this part of the system is working. The other side of the system the White/Green wire also supplies (via the engine fuse box) a Brown/Grey wire which goes directly to the passenger fuse box which contains the Intellegent Driver Module and this in turn controls the hazard warning lights and the Central Door Locking via the BCU.

As you have had the passenger fuse box and BCU replaced and you still get the fault then we can assume that the problem is before them.

So, for me, it appears to be very straight forward and you also have given a crucial hint. I would first check the continuity of the Brown/Grey wire from the engine fuse box (connector C0605 Pin 4) to the passenger fuse box (Connector C0586 Pin12) you should get a reading of around 0.3 ohm. Next I would check the continuity between connector C0605 Pin 4 on the engine fuse box and connector C0605 Pin 3 on the engine fuse box.

I suspect there is a break in one of the above and it occurred when they removed the ECU next to the engine fuse box. I would also check for corrosion on the underside of the engine fuse box.

This is the relevant circuit diagram

ANTI-THEFT ALARM.pdf

(109.27 KiB) 511 keer gedownload

Oh and as an aside, they did reconnect the earth strap on the earth cable back onto the body when the disconnected the earth cable from the battery

Rob (who also had only a couple of Dutch lessons (16 years ago) )

[Nchanga55]

Thankyou for the replys Gents,

Rob, thanks for the top effort mate, its a bit above my pay scale but we are talking to an electrician who deals with landys and this information will be invalueable.

I disconnected the inertia crash sensor and briged pins 1 and 3 and the fault comes back after 20-30 seconds.

The only thing I could assertain from your explanation was that the earth is re-connected.. I did remove the ECU for a visual but saw nothing obvious, however when i (carefuly) replaced it and started the car the fault comes in instantanious so I've angered something...
Ill see what the electrician says....

If there is a problem with the wiring I presume I would have to order a new harness??

I will keep you posted...

Thanks again, i was begining to give up hope.

Sean.

[RobStewart]

If there is a problem with the wiring I presume I would have to order a new harness??

Hi Sean,

It's looking more and more like a wiring/fuse box fault. If it's the brown/grey wire between the engine and passenger fuse box then you don't need to replace the harness you can splice a new wire in. If the fault is internal to the fuse box then it would depend on how bad it was.

Rob

[Nchanga55]

Hi,

Its been a while but the fault is fixed. I found an indipendent landrover enthusiast with his own garage and following Rob Stewart's exellent and detailed advice we fixed the fault for 90 euro's.

It was the brown grey wire which had shorted somewhere so we spliced in a new one and hey presto... I can drive the car and use the indicators!!!!!!!

Rob send me a private message with your address mate as I would like to send a gift as a thanks, without your invaluable advice i would still be driving around with a Disco that thought it was a christmas tree......

If anyone in the South Holland area doesn't fancy being taken for a ride by a certain main Landy Dealer please give this guy a shout. Hes a top bloke and we fixed the fault in three hours after Land Rover had given up (obviously with Robs advice).

http://www.reparatiebuddy.nl/monteur/42 ... laardingen

Many thanks again, and thank you LRCH for making it all come together.

Sean. ( a very happy little camper)

[RobStewart]

Many thanks again, and thank you LRCH for making it all come together.

Sean, I'm really pleased that your problem is solved and that it did indeed turn out to be a simple fix.

I hope this means you are keeping the Discovery and that we get a chance to meet up on one of the Club events.

Rob.