Weird Electrical Phenomena

Evening All

"oh yes another L322 thread to go with the growing list"


Anyhow...

not had any probs for a few months so i guess i have been lucky for that time lol

came to start my car this morning, first time the glow plugs have kicked in this year to pre-heat.

anyway, turned on ignition and started car, all ok. drove about 50 meters to my garage and turned off the car. came back to drive off and turned on ignition... and the hazard lights started ??

oh well, just thought i might have accidentally hit the button on the dash.

thought nothing of it until i tried locking my doors from inside the car, ie using the dash switch.. they wouldn't lock for some reason ? they used to lock fine as i always lock the doors when i go for a drive


got to destination and turned off car, then put ignition back on to try it again... the same thing happened ! hazard lights come on and the doors wont lock from the inside.

i have also realised once you have experienced the flashing hazards situation and you try locking the car from the outside, the doors wont lock when pressing the fob, just the hazards flash like they would usually do when locking / unlocking just the doors don't actually lock / unlock.

you have to press the fob a few times to get the car to lock as normal.


I'm totally stumped ?


having read up on a few problems on line it seems to be something with the alarm at fault ? something about a crash sensor ?? when you have a crash this sensor detects the impact and automatically puts the hazards on and opens the doors. sounds like this is why it wont let my doors lock, it thinks its had a crash maybe ?

once you finally get it to start locking from inside i have noticed if you lock the doors from the inside using the dash switch, then turn the ignition on the hazards flash as before and the doors automatically unlock ?

does anyone have a clue if im on the right track ?

All comms shows a connection error when trying to open comms with the "security alarm module" ? could that be the problem, a canbus fault ?

or could it just be because i have a HSE and they might not have the security module like the vogue's ? For instance, if a module isn't present, it shows the same connection fault because its not there ?

Sorry for the essay write up, its hard to explain in short

Thanks for any help you may be able to give me

I would defiantly go with crash sensor.....

Where do you park? Could some numpty have reversed into you whilst you where away from the car and then driven off??

* Just to add, i have tried pulling the fuse on the Anti theft, and all the immobilisers fuses to try and reset something. none are blown neither has it reset anything

Saint.V8 said:

I would defiantly go with crash sensor.....

Where do you park? Could some numpty have reversed into you whilst you where away from the car and then driven off??

Click to expand...

out street is parallel parked, and no damage to car, so it cant be from a shunt

Does anyone know where this so called "crash sensor" is located ?
Is it even replaceable ?

Cheers

According to what I read the 'crash sensor' is part of the SRS system so should only operate if the airbags are fired. So I'm thinking that you've got a confused electronic module, possibly a battery disconnect is in order? Just be careful if you've got the explosive lead!!

Sorry, don't do linkies but is this any use?
landrover.workshop-manuals.com/l322

Battery voltage good?

thanks for your help guys.

well first things first... checked the battery. voltage seems ok..... so went to do a hard reset (disconnect the battery)

well.... found that the negative terminal was loose, ie i could spin it around on the post easily !

thought i may have found the problem ! so went ahead and disconnected the battery for 10 mins and then reconnected and tightened the terminals properly.

problem still exists !

as "dogsbody" mentioned above the fault may be part of the SRS system.

which made me think could it be anything to do with the fact my SRS light has been intermittently coming on and off recently ??

i thought i had narrowed it down to a bad connection under the passenger seat on one of the connections, as I fiddled about with the connections last time the light come on and it seemed to clear the light for a few weeks untill last week when my SRS light come back on.


All comms states something to do with "passenger buckle switch" !

but mine doesn't seem to have any buckle switches ??? i thought only the euro models had them fitted ?

when resetting the fault, the SRS light flickers on and off (like a bad connection somewhere" until finally staying on constantly.

sounds like i have an intermittent problem somewhere ?

could this link with the hazard lights problem im experiencing ?

but i have read it could also be the SRS ECU failed ?

I dont know where to start

Probably teaching granny to suck eggs, but don't mess around with any SRS/airbag related wiring or connectors with the battery connected.

StuckAgainSteve said:

Probably teaching granny to suck eggs, but don't mess around with any SRS/airbag related wiring or connectors with the battery connected.

Click to expand...

I know mate, they can be deadly from what i have heard.

but thats the only way you know when you have found the culprit connector as the light on the dash goes out.


might have to cease DIY and hand it in to my cousin who consequently is the manager of a Land Rover Dealership

i dont like being beaten

2.0_hippo said:

Does anyone know where this so called "crash sensor" is located ?
Is it even replaceable ?

Cheers

Click to expand...

There is a side impact sensor at the base of both B posts,behind the plastic trim

Planny said:

There is a side impact sensor at the base of both B posts,behind the plastic trim

Click to expand...

Thanks mate !

surely if it was one of these sensors at fault it would show on diagnostics ?

I can't find anything about a 'buckle switch' as there are occupancy sensors in the seat squabs. However the next things down from the buckles are the pre-tensioners. I'd definitely get myself away from them and pass it to your cousin.

having a read...

"Crash Signal
When the DCU outputs any of the fire signals it also outputs a crash signal to the Body Control Unit (BCU) and the
ECM. On receipt of the crash signal, the BCU goes into a crash mode and the ECM cuts the power supply to the fuel
pump relay. In the crash mode, the BCU:

l

Activates all of the unlock signals of the vehicle locking system, even if the vehicle is already unlocked

l

Ignores all locking/superlocking inputs until it receives an unlock input, when it returns the locking system to
normal operation

l

Activates the interior lamps. The interior lamps remain on permanently until they are manually switched off at the
lamp unit, or the BCU crash mode is switched off and they return to normal operation

l

Disables the rear window child lock input until the crash mode is switched off

l

Sends a crash message to the Light Check Module (LCM), via the K bus, instrument pack and I bus, to activate
the hazard warning lamps. The hazard warning lamps remain on until cancelled by the hazard warning switch or
the crash mode is switched off.

The BCU crash mode is switched off by a valid locking and unlocking cycle of the locking system"


exactly my symptoms, and i even notice after reading that my interior lights stay on until i turn them off manually just as stated in the above paragraph

maybe i could change the SRS ECU ?

digging even deeper....

found a post on another RR forum regarding faulty BCU (Body control unit) ECU's on early L322's...

"Its a technical bulletin affecting up to VIN 4A 162652 of the Range Rover (LM). The problem involves a false crash input signal to the BCU part number YWC00921 which causes the hazard lamps to flash, doors to unlock, radio to mute and the interior lights to illuminate while driving. The problem comes from an electrical spike within the internal circuits"


- sounds very promising to me.

as if the airbag ecu had sent the crash signal the airbags should have gone off, my fuel pump should stop.. etc.. but they haven't obviously.

and i reckon my SRS fault is nothing to do with this as i had the SRS fault months before this BCU fault

ill get there in the end

That sounds very hopeful - until you come to the bill of course
I'm not having a dig at L332s it's just that when you start playing with any SRS system it's rarely cheap.

dogsbody said:

That sounds very hopeful - until you come to the bill of course
I'm not having a dig at L332s it's just that when you start playing with any SRS system it's rarely cheap.

Click to expand...

indeed, it sounds hopeful.

found one of the updated BCU's on ebay but after reading it seems it needs programming to the car as the BCU stores key codes etc...

:doh:

FML

get it on diagnostics asap?

donp38 said:

get it on diagnostics asap?

Click to expand...

I have, only one fault on the SRS module which i dont think is related to my problem.

ill have another look on the body control ecu settings tomorrow.

might try it with the hawkeye diagnostics too and see if that see's any more than the all comms

Well another check on diagnostics tonight with a hawkeye...

If I bring up the hazard fault and then connect diagnostics and go to BCU module

Brings up fault "crash sensor constantly active" ?!??

And a few other errors that don't seem right

I have a feeling that its the body control ECU that's gone tits up and it's throwing up these faults ?

As if the actual airbag crash sensor had activated surely the airbags should have gone off to ? ?

As well as there being a known fault with the early ecu's bringing up a "crash" fault just helps me confirm a faulty BCU even more.

So if I'm going to change the body control unit .. Is it only the remote fobs that will need re-programming or is there more involved ?

Cheers guys !