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W639 Vito Starting Fault

phil24/7

Member
Joined
Feb 24, 2015
Messages
32
Location
Plymouth
Car
Vito (W639)
My Vito has developed a starting fault.

For the last 2 weeks when trying to start my Vito there is a click and turn from the starter but it doesn't turn over. If you keep the key turned a second or two later it will do the same again. It will keep doing this until the key is released. The lights don't appear to dim majorly whist this is happening.

It didn't seem like a flat battery fault as the starter normally clicks, the dash lights flicker and then you have to turn the ignition off and on again for the starter to do anything else, there is no second click

All seemed to be working fine after leaving it running for a couple hours so it appeared to be a low battery. It had never behaved like this before so I was wondering if perhaps the starter was a little sleep and requiring more juice to turn over. Anywho, I replaced the battery and all was fine for a few days, then the fault returned.

The starter was then replaced with no change!

As mentioned, if the vehicle was left running for a couple of hours it would start straight back up, even after a few hours. Likewise if the van was bump started, it would straight straight back up. If the van was left overnight, or through the day at work, it would need bumping or jumping upon my return!

I had an auto electrician out to look over it and he tested the battery and charging circuit and said all was fine. Charging at over 14v battery at just over 12v. Tested my amp by pulling the fuse but there was no change, it still wouldn't charge.

Like I said, it has had a new battery (uprated Bosch battery) and a new starter motor so these are definitely ruled out.

The sparks did say that when the ignition is turned on there is a drain and this is taking volts at the battery down to below 12 (11.6 I think). He said this may then be too low so it is kicking the immobiliser in. If he bypasses this and manually activates the started it turns no problem. All the interior lights have been replaced with LED's and all turn off when they should so it isn't the lights causing the drain.

He's back tomorrow to have a look again and see if he can get to the bottom of it. He seems to recall his mate having a similar issue and he needed a new ignition switch...which will then probably need a matching ecu etc!!!

Anybody had any similar issues or got any ideas?

Regards
Phil
 
It doe sound like an EZS problem, give Mark at Mercedes replacement keys a ring.
 
Ah shoot! What's involved with this. Can the EZS be repaired or is it a new ignition? Am I right in assuming you need to replace the ECU if the EZS is renewed?

Cheers for the speedy reply.
 
Thank you all kindly. I will call him later.
 
Spoke with Mark today. Seems like a nice bloke and not a penny pincher. Suggested a few things to try before I send my ignition and ecu to him...just need to fine time to strip the ignition and ecu etc out of my brothers vito to try in mine!
 
Bit of an update. The auto electrician found that if you turn the ignition quickly to start, it will (this is with a charged battery) but if you pause after the ignition is turned on before cranking over, it just clicks. He then got it to start again once it was turned quickly.

I have now recreated this.

I am leaving the van running all day to fully charge the battery so that I can try to identify the source of the drain so need to check all ignition and starter wiring along with any associated fuses or relays.

Not a happy boy and I don't have the time to strip 2 vans to fault find the ecu/eis etc!
 
EZS comes out in 2 mins max and the ecu is in the black control box again 2 mins.
 
In addition.

Yesterday I left the van running most of the day. Turned it off an hour before I was due to come home. When I tried to start it to come home all the lights came on but nothing else happened, not even the usual clunk from the starter. I bump started it and drove it home. Once home I turned it off then tried to start it again and it was back to doing the clunks but not starting.

Had to put jump leads on for 20 mins this morning before it would finally turn over and start so I think either the drain or the fault is getting worse.

Off on holiday for a week on Sunday so when I return I shall be swapping the relevant parts over from the 2 vans to see if I can get it sorted!

Thanks to all for the suggestions and help so far.

Regards
Phil
 
It is a bit of a basic answer, but could it be as simple as a faulty battery.? (or a broken/loose battery cable or ground strap).
 
Cheers Zen. I take it the van would start without the right steering lock but the lock wont release?

Should be able to knock something up or borrow the tool off of somebody as I'm a director for a commercial vehicle repair garage.

StMarks - Just had a new battery and it, along with all battery main wiring and the charging circuit, was checked by an auto electrician.
 
...StMarks - Just had a new battery and it, along with all battery main wiring and the charging circuit, was checked by an auto electrician.
Fair enough, I did think it was a little unlikely that that had not been considered early on.
Fwiw I only suggested it because an acquaintance of mine was recently stranded after the new (premium brand) battery that he had fitted only a few weeks earlier failed.
It was replaced without quibble, but apparently was caused by a "manufacturing flaw".
 
The simple things often get missed and batteries can often sit on a shelf for a long time before being sold. I've had more than 1 that has been past it's best when I've received it.
 
Had the aouto electrician back yesterday and after some testing with a laptop connected he has said that the starter relay seems fine and the ignition is sending a 'start' signal down to the ECU when you turn the key so he is leaning towards the ECU at fault. He has gone away to ask a couple of colleagues (1 of whom repairs ECU's) for any experience with this issue.

Today I have swapped the ECU and ignition from my brothers 54 plate van with my 06 van but it would not start, in fact the key would not even turn. Tried my stuff in his and the same thing. Think I need to swap the steering lock over too but that seems to be a lot more involved than just swapping the ECU and EIS!
 
Managed to find a pdf detailing the steering lock removal and it doesn't look too bad so I will have a go at removing mine tomorrow and then swap over the whole lot from my brothers van.
 
I eventually managed to remove the steering lock yesterday. A tip for all those looking to do it is to turn the retaining pin as if your undoing it...this way you wont butcher the star head of the pin!

I swapped all 3 parts from my brothers van and the same thing happened. Just to double check I put all my stuff on my brothers van and it started first time.

Good news: The ECU and the EIS are fine
Bad news: Back to the drawing board as I now have no idea what the problem is again!

Will get the auto electrician back next week for some more fault finding...wish me luck!
 
.....Will get the auto electrician back next week for some more fault finding...wish me luck!
:thumb: Best of luck Phil.

If the starter relay is ok, presumably it's "just" a case of the technician tracing the relay activation supply back to work out where it is fed from.?
 
Cheers.

When the sparks tested on Monday, he said that the ignition was sending a signal but the ECU didn't appear to be sending this on. I know this isn't true now so I think I may need to start continuity testing some wires!

I hate electrics!
 

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