Mercedes Vito Breakdown

Sunday
After church on Sunday, Megan loads the Vito with children to take home.  The plan is to come back and with my help, load the marimbas into the Vito.  The marimbas had been placed in the church meeting room on Friday night after they were used at the streetparty.  It had been raining and this was to give them a chance to stay dry.  I went to the coffee club to get a coffee.  Nice to have some down time in a busy weekend.

My phone rings and it is Megan.  The Vito wont start and she and it are near the corner of Dewar tce and Marlbrough st.  Not far so I walk.  I arrive and the fault is not abvious so we call the RACQ.


Fault Description:
Everything seemed good - lights come on, key locks & un locks the doors, and when you turn it, the lights come on on the dash but when you turn it to the start position, the engine does not crank.  The engine warning fault light stays on after the lamp test cycle is complete.  (The manual says this is a exhaust or fuel issue (bizarre as later I find on the internet that almost every issue results in that light coming on).  (yes there is fuel).

Historical information:
On two or 3 occasions in the last few months, with engine running and the gear leaver moved to the Park position, the vehicle displays "R" even though it is physical in the "P" position.  The gear leaver would then be jammed in the P position.  This fault could be cleared by switching the engine off and then restarting.

RACQ
The fellow dutifully arrived and I described the above to him.

He checked the battery was OK but then seemed to get a bit lost.  At one stage he got under the vehicle and used a screwdriver to short something out and encourage the engine to crank but of course it did not start.

I asked if he could plug in a diagnostic tool and he said his tool would not read Mercedes codes.  He did not attempt to plug in his tool.

I asked him if he should call for more information.  He initially misinterpreted that question and responded that Mercedes do not send their own techs that they just call RACQ.  I clarified that I meant call RACQ and speak to a guru but he didn't do that.

He said that he thought it was the ignition inhibit circuit.  I was not so sure given that the key correctly operates the door locks.  We discussed getting the spare key from home (20 minutes).  He seemed keen on that idea.

He said that it was too hard and that we would have to tow the vehicle.  He offered to organise that but I declined as I figured we would try the spare key and anyway I did not know where we were going to tow it to.

He helped to push the car out of the driveway so that we were not cloging up the persons driveway.

He then went on his way.




OBD2
I called my friend Ross and borrowed his $20 Ebay OBD2 Bluetooth doodad.  Downloaded an app called Torque.  The free version did not do anything much so I figured this is all going to cost a fortune so I figured $4.85 for the pro version may be worth it. 

While I had been waiting for the RACQ fellow, I had established that I did not know the location of the OBD2 connector and google seemed confused.  So on my way to Ross's house I dropped into home to use a real computer to search the net.  It is above the accelorator pedal.

The ODB2 dodad told me there were 4 errors and one was highlighted in red as a "Current Fault".  With little information and no experience, I saved that information and then sent the clear command.  This cleared the errors with the exception of the A/C error.  But still it would not start.  Gave up and went home.

On Monday, I phoned Ash Prestige Auto Repairs at Graceville.  Then orgainsed the RACQ to tow it there.

Tuesday Ash call's me and for $308 I can have my Vito back and all that they found wrong was a fuse in the starter motor circuit.

You're kidding.  I was annoyed with myself for not checking the fuses and I was annoyed the the RACQ fellow for the same reason and at the time suspicious that he had actually blown the fuse while messing around with his screwdriver shorting things out under the car to make it crank.

FRIDAY 16-11-2012
I am at work and my phone rings.  It's Megan and the Vito wont start again and Jemma has to be at gymnastics.  There is an added complication this time in that the Vito is low on fuel and it is suspected that that may be contributing to the problem.  I talk Megan through where to plug in the OBD2 dodad and how to download the App.  The theory is that we may be able to clear the fault and start the engine.  As a backup, I jump in my car and drive home. 

I arrive home and the Vito is still stuck.  Time is fleeting, madness takes it's toll... So I grab Jemma and take her to Y-West gymnastics.  Back home and my phone connects and we see

U0404 - Network - Tap "Web for more information"
So I do and the phone goes to www.dtsearch.com
and that web site tells me that U0404
"Invalid Data Received From Gear Shift Control module 'A'"

So I think we would all agree we have a comms issue amongst other things.

I clear that and now it reports no errors but still it wont start.

Time to pick up Jemma so I drop into Bunnings and buy a (plastic) fuel can.  Pick up Jemma and then buy 10l diesel.  Pour in the diesel and it makes no difference.  Not that that really surprised me but it ruled that out.

Megan takes the Tiida to P1 and Chris, Dan, Jemma and I walk round tor swimming club.  After they are signed on, I walk home

Not wishing to spend another $300 to find a dead fuse I look carefully over the fuses and what do you know there is a blown one.  At some stage I have bought or been given a handy pack of replacement fuses and so the fuse is replaced and the engine now cranks and starts.  I did through the owners manual and what do you know, it is in the starter circuit.  My assumption is that it is in the control circuit for the starter solenoid which in turn provides the power to the starter motor.

THEORY
a) We have two unrelated faults
    .1 The issue with the gear selector
    .2 The starter motor solenoid not pulling in and pulling too much current.
b) The faults are related - Perhaps the gearbox controller is doing something such that when the starter operates that it does not let go at the end of the previous start or perhaps it jams for the current start cycle. 

It would be nice to know WHEN the fuse blows.

RESEARCH
Need to find a service manual or at least a wiring diagram.
A tame expert who is not going to charge me $100 an hour to debug & fiddle.   

http://www.justanswer.com/mercedes/5262r-07-vito-115cdi-blows-fuse-16-whenever-turn-key.html
Fuse 16 blows.  Traced to frayed wiring harness.  As part of the debug process, he disconnected the wire to the starter motor and the fuse still broke.