Hit a speed bump and van shut down and came to a stop. Scan shows numerous module communication errors.

Jollyvan said:
So pleased that you are sorted. Why did his scan work when your VCDS did not?
As you say a bit worrying.
Click to expand...
Not sure Rob. Mmi has suggested that trying to clear dtcs in auto scan is not always successful.
But thinking back, the roadside assistance guy couldn’t clear the codes either when the original incident occurred.

I’ll drive it for a few days locally and hit a few speed humps (nothing big lol) and see what happens I guess.
 
Pauly said:
I feel robbed, i need to know what went wrong, this accidental fix just doesnt work for me !!
Click to expand...
totally agree,

these are the worst fixes.. . . . im almost hoping for a repeat fault.
 
I'm hoping the same gods that fixed my coil light coming on last winter never to come on again, have smiled kindly on the one they call 'Bigsi - provider of culinary delights' and will cause him no more harm.
Love you man! And worryingly so does my Mrs, you having saved her from starvation after a long shift when she finally got to Autumn Camp!
 
So another update.
Good and bad.
The van hasn’t moved for a few days since the codes were cleared and it was miraculously fixed.
Today I decided to put the dash back together in stages and test the van at each stage.
Ecu back into carrier - starts no faults
Obd - same
Lower centre of dash (the bit that goes over the gear lever and has fuse box cover etc) - all faults return and van is back to exactly how it was when I hit the speed bump.
The only other thing I did at the same time was to put my weight on the double passenger seat which has a swivel base and all the wiring and connectors crammed under the floor mat.
The bonnet has not been opened and nothing disturbed elsewhere.
So hopefully this is good news as it points to the wiring fault being inside the cab, and maybe under the seat.
Auto electrician is hoping to come back on Monday.
So glad I didn’t go anywhere in the van before this inevitable repeat occurred stranding me.
Happy(ish) and hoping for the fault to be found and fixed.
 
oooh, that sounds promising.

from memory you moved all the passenger seat base connectors under the carpet when you fitted the swivel thing. . . .

you think there maybe a cable fault there?
 
you not tried using VCDS to clear the faults,

to them press and prod around to replicate the issue?
 
Auto electrician has been. Hoping it would be a quick fix, but everything under the passenger seat seems ok. It's going to have to go to his unit so he has power etc, furhter investigation not do-able in minus 3 on the main road.

However, whatever has been disturbed/shorted causes all the attached fault codes to appear together immediately and also causes the fuel lift pump to stop working.

I've attached a VCDS scan taken immediately after the most recent reoccurence. The only thing I did was put the centre under dash trim back, sit on the passenger seat and rummage in the big clump of wires that go from the bottom of the dash below the gear lever and under the centre of the floor mat, trying to find a screw I dropped. Immediately prior to that the van started perfectly.
I know we have some mega-electrical gurus on here so wondering if it could be one obvious issue. @mmi and @n10n any ideas of one cable/cable route that is coomon to all these problems?
 

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Bigsidavies said:
Auto electrician has been. Hoping it would be a quick fix, but everything under the passenger seat seems ok. It's going to have to go to his unit so he has power etc, furhter investigation not do-able in minus 3 on the main road.

However, whatever has been disturbed/shorted causes all the attached fault codes to appear together immediately and also causes the fuel lift pump to stop working.

I've attached a VCDS scan taken immediately after the most recent reoccurence. The only thing I did was put the centre under dash trim back, sit on the passenger seat and rummage in the big clump of wires that go from the bottom of the dash below the gear lever and under the centre of the floor mat, trying to find a screw I dropped. Immediately prior to that the van started perfectly.
I know we have some mega-electrical gurus on here so wondering if it could be one obvious issue. @mmi and @n10n any ideas of one cable/cable route that is coomon to all these problems?
Click to expand...

I really wish I could tell what the issue is. Anyway has to be something regarding major supplies, grounds or databuses.

I guess I would first check the ground points at under seats, the easy ones at left and right A-pillar bases and the nasty one somewhere at the center channel from gear stick to between the front chairs.

The big wire lump that goes in the floor channel to under the seats and then under the van rings many of bells in the fault list. But not all. So indeed searching for the screw from that area might have moved the wires just enough to reintroduce the issue. Reverse could be also true so just lifting the wire lump a bit from different positions, putting some lego bit under and cycling ignition might make everything work suddenly - doing this repeatedly in various positions could help to point out the location.

Then maybe systematically pulling fuses, one by one, from the main fuse box and seeing if the amount of faults could be reduced or changed that way might be a tedious way to narrow down which circuit the issue is within.

I’ll try to browse wiring diagrams to see if I can come up with further ideas. At this point though I don’t unfortunately have any more specific advice to give - I really hope you find the issue and it turns out to be something simple. And probably it is something simple but finding it may take lot of work.
 
One specific thing that caught my eye from the scan is the very low Terminal 15 (ignition on) voltage reported by the steering angle sensor.

Maybe a clue

IMG_4582.jpeg
 
Last edited:
Bigsidavies said:
also causes the fuel lift pump to stop working.
Click to expand...
Please elaborate a bit.
a) Did you run VCDS > Engine > Output test > Fuel pump electronics - and didn't hear the pump (cycling on and off every four seconds)?
b) Did you run VCDS > Engine > Basic Settings > Test of Transfer Fuel Pump (running the pump continuously) - didn't hear the pump?
More details
www.t6forum.com

[T6_measured] 01-Engine - Built-in test for Transfer fuel pump

A quick DIY way to test fuel lift pump's basic functionality. The test takes advantage of engine's fuel high pressure sensor (in fuel rail). Running the lift pump continuosly makes the pressure eventually "leak" through high pressure pump and can be detected by fuel pressure sensor. As a side...
www.t6forum.com www.t6forum.com
 
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