Starter engages when ignition switched on !

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HeliMurf

New Member
Posts
7
Location
Abersoch
Starter engages (!) when key turned to ignition position (not the start position, the position before that !)
Also, starter motor keeps spinning after engine starts.
Obviously, I switch off sharpish !
Suspect damp has something to do with it ?
Has anyone any ideas about this, please?
This first happened when I found that my electric windows were not operating and, at my local garage, we took out the windows fuses, found they were OK, put the fuses back and while we were discussing why the windows should have started working again just because we took out the fuses and replaced them,(the ignition had been left on to try the windows function) the engine suddenly started, right out of the blue, and she took off in reverse ! (I had always left her in gear, but shall not again !)
I managed to dive in, feet first, and stall her with the footbrake, just before she took out the petrol pumps, several passing tourist children and the plate-glass window of the local store ! (did £400 of damage with my open door to the mechanic's new car, parked alongside and bent the hell out of my door, too !)
We then found that the windows had decided not to work again, by the way.
We disconnected the starter motor and I roll-started her for the rest of that day.
The next morning I found that the windows were working again so we reconnected the starter motor and everything behaved properly for about a week, until this morning, when I turned on the ignition and the starter engaged immediately and would not stop spinning until I turned off the ignition.
Also, once again, the windows don't work.
I have left everything open (doors, bonnet, etc) since this morning, on a sunny warm day but she still won't behave.
Any ideas, please ?
Yours in desperation,
  • Pauli Murphy :-( (aka HeliMurf) Please email [email protected] or text 07768-603365 in case I'm not logged on. THANK YOU !!!!
 
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these two faults could be connected and then the BCU(body controll unit) behind the glovebox is involved.. ...it's common to suffer by water ingress/moisture..and that's bad news...check for corrosion at it's contacts(it's the one with 4 plugs at the bottom and one at one side, eventually open it and treat it with this stuff http://www.ebay.co.uk/itm/NANOPROTE...T-/221156844180?ssPageName=ADME:X:RTQ:GB:1123 , maybe you're lucky and it didnt get very harmed

but these faults could be separate aswell

for the starting issue to rule out a sticking relay replace the starter relay R2 in engine bay fusebox...if it will not cure it you can let this relay out and start the car bypassing it's contact to crank untill you trace the fault

it's quite complicated and needs some measurements to make sure about some things

also the interior fusebox which manages the windows can have water ingress problems

if you want to make investigations disconect the battery before you play at the BCU... see quoted parts maybe you'll get an idea...and dont dissapear if you fix it... like other newbies i helped did

1. Starting and Charging Description
The starting system comprises a starter motor and solenoid located at the rear
right hand side of the engine. A starter relay, controlled by the Body Control
Unit (BCU), supplies battery power for starter solenoid operation. The starter
motor receives its feed directly from the battery.
Starter relay operation
When the ignition switch is moved to the crank position III, a feed passes from
the switch, through fuse 23 in the passenger compartment fusebox to the coil
of the starter relay in the engine compartment fusebox on a WR wire.
The coil is earthed to the BCU on a BO wire. When the BCU determines that
starter operation is allowed, the earth path is completed and the starter relay
energises, closing the relay contacts.
The feed from fusible link 12 passes through the starter relay contacts and is
connected from the engine compartment fusebox to the coil of the starter motor
solenoid on an NR wire. The coil energises, closing the starter motor solenoid
contacts. The coil is earthed via the starter motor body.
The feed from the battery positive terminal passes through the closed contacts
of the starter motor solenoid and operates the starter motor. The starter motor
is earthed through the motor body attachment.
When the ignition switch is released, it returns to position II. This terminates the
feed from the ignition switch to the starter relay coil, de-energising the coil and
opening the relay contacts. This in turn removes the feed from fusible link 12 to
the starter motor solenoid coil, opening the solenoid contacts and removing the
battery feed to the starter motor.

2. Windows - Front Description
The front windows are electrically operated from two rocker switches located in
the centre console. The front windows are controlled by the Body Control Unit
(BCU) which limits the operation of the windows to when the ignition is in
position II and for a period of 44 seconds after the ignition is switched off or
after the driver’s door is opened. The front window operation is suspended
when the ignition switch is in the crank position III.
The front windows are powered by electric motors located in each front door.
The window up/down functions are controlled by reversing the polarity to the
motors. The BCU logic circuits have a stall detect function that monitors the
current drawn by the window motor. When the window contacts the top of the
door frame or an obstruction the current drawn by the electric motor rises. If the
BCU detects a sudden current rise the internal logic will remove the power
supply to the front window motor.
The front windows have a one shot down function which operates if the switch
is pressed for less than 0.4 seconds. Operation of the switch for more than 0.4
seconds operates the windows in inch down mode. The windows stop when
the switch is released.
The front windows only operate in the inch up mode for as long as the switch is
pressed. The windows stop when the switch is released.
Fault conditions related to the front windows can be retrieved from the BCU via
the diagnostic socket using TestBook/T4.
Click to expand...
 
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Sierrafery !
Thank you SO much for your kind, comprehensive and prompt reply to my cry for help !
I very much appreciate the wealth of information you so generously sent to me !
I've never even HEARD of a BCU and was thinking I might have to replace the ECU (engine control unit) which is expensive.
I will print out your excellent advice and take it with me to a mechanic who has a diagnostic computer and see what we can find out.
I, too, have had an engine re-mapping plus a much larger intercooler fitted recently and she goes well ! (I also fitted a stainless steel, straight-through exhaust)
I will let you know how I get on with this "problem" in due course and, again, thank you for your most kind and helpful information !
Yours Aye,
Pauli Murphy (also known as HeliMurf) :)
 
welcome... be aware that the Disco 2 BCU doesnt comunicate with OBD generic diagnostic tools...it must be a dedicated L.R. tester to "hook" to the BCU... as you have a D2 and want to keep it you better download a free RAVE(search the forum or the web and you'll find)...this is the complete PDF manual which covers all the systems and diagrams, (the quoted part from my first message was from RAVE)...good luck
 
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My local garage, with the OBD generic diagnostic device DOES communicate with the BCU, they tell me.
He is going to check through everything on Friday, the 4th of October, including all the relevant wiring, using a full, downloaded wiring diagram for the vehicle plus the OBD.
He has read all your kind words and does not disagree with anything you said.
I will let you know how I get on, of course.
The biggest problem is that the 2 faults (together and separately) are completely intermittent !! Sometimes they work, sometimes not !
Kind regards,
Pauli (aka HeliMurf) :)
 
Hi , you seem a nice guy to me so i tell you with 100% warranty that the BCU DOES NOT COMUNICATE WITH GENERIC OBD on the fault condition area, maybe if it's a smarter generic tool it would actuate some things in the BCU like warning lamps or security settings but it would not enter in the core of it.... i want to protect you from being robbed so ask them on the phone what kind of tool they have(the name of it) and report back ...i can tell you if it comunicates or not, i give you some tools which are comunicating and if theyrs tool is one of these go with confidence, if not IMO you'll pay in vain: Omitec T4, Autologic, Dec Superscan, Lynx, Tribox Mobile, Launch Extreme, Faultmate, Nanocom, Hawkeye... though these are not generic OBD tools but multivehicle tools or dedicated L.R tools.

the fact that they say that the Discovery 2 BCU is OBD compliant is suspect for me from the beginning ...and if they would have contradicted my statements believe me they dont have a clue about that. Your choice m8
 
OK, thank you again for your advice.
I have not asked them about the OBD/BCU communication question since I have not been logged on 'til just now, AND I have taken a step that I felt is a compromise, and which may NOT prove to be a conclusive solution, but it only cost me GBP£50, total.
Because of the 'intermittent' nature of both problems, and because (as luck would always have it) the problems refused to make themselves apparent when I was at the garage, with everything working properly, we agreed that they would take out the glove box and examine whether or not there was any evidence of water ingress to the BCU.
This was done and there was NO evidence of any water damage or ingress at all.
Then, at my request, they fitted a push-button starter-engage switch (very neatly, -it even looks as though it was fitted as standard !) on the dashboard which will only allow the starter motor to engage while the button is pushed. Having disconnected the starter relay from the ignition, it means that, whenever the ignition is switched on, the starter motor CANNOT engage unless my new push-button starter-engage switch is pushed.
OK, this means that any malfunction of that aspect will now always be both obviated and also undetectable but I am happy with that.
The windows have, on one occasion, continued to malfunction BUT they always (now) agree to function properly after the ignition is recycled. (engine switched off and then ignition switched back on again) Since this modification to the starter system, the windows have only malfunctioned once, out of, perhaps, about 30 starts.
SO - we have decided to leave things as they are, rather than throw any more money at the problem. If things deteriorate, then I may decide to obtain and fit a second-hand BCU to see if that might fix things, but meantime I will leave things as they are.
I will, of course be most grateful and interested in your opinion, if you care to take the time to advise me of what you think, my Friend.
I will log in again in a few days time and meanwhile, I thank you once again for your kindness.
With best regards,
Yours Aye,
Pauli Murphy (aka HeliMurf) :)
 
OK, you found a way to fix it for now...but , IF the BCU started to do tricks it's possible this will get worst in time and you might end up immobilised so you better fix it for good...meanwhile you can check for water ingress at the interior fusebox too just to make sure the IDM is not affected.
 
Well, Sierrafery, I believe I have come to a place where I am happy enough for now, although I do agree that it would be better to ensure that the BCU is replaced, but it is a question of costs, so I will leave things as they are.
We did check the interior fusebox and there is no sign of water ingress, so I am trusting that the Intelligent Driver Module (IDM) is not affected.....
I do thank you for your guidance and advice. It gave me the confidence to get on with finding a solution, knowing that there was someone who cared enough to lend me helpful tips from a sound knowledge base.
Much Appreciated.
Yours Aye,
HeliMurf :)
 
i hope it will not get worst then;)... as long as the BCU doesnt get mad on the engine immobiliser side of it everything is bypassable, but if at one point a crossed B will appear on the odometer then hurry to replace the BCU cos the immobiliser will kick in soon too, and no pypass would help then...good luck
 
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