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

[Bigsidavies]

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

[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

I get a VCDS error when trying to test lift pump. The auto-electricians obd tool is unable to activate the lift pump.

 

[Rioja John]

Any news on your van Si?

John.

 

[Bigsidavies]

Any news on your van Si?

John.

It’s going to the auto electrician’s unit next week to be sorted.
However, I stepped over to open the passenger door from inside yesterday putting only one foot in the centre of the floor mat to reach across, and on getting back out dash warnings had gone and hey presto it started first go.
So…….. I guess the issue is in the wiring under the centre of the floor.
Seat and leisure electrics are coming out tomorrow then removing the flooring mat and seeing if there’s anything obvious.
It’s starting to annoy me now tbh.

 

[oldiebut goodie]

Following that - is there a cable trapped under the leisure battery (if fitted)?

 

[Bigsidavies]

Following that - is there a cable trapped under the leisure battery (if fitted)?

I’m pretty sure there isn’t. It’s under the driver’s seat.
The fault re-occurred a couple of weeks ago while I was re-fitting the lower centre dash panel (the one that covers the fuse panel and goes over the gear lever) from the passenger side whilst kneeling and leaning on the floor mat in front of the handbrake.
The fault fixed itself yesterday when I stood in exactly the same place. There’s a few of the original fuses and relays fitted to the seat frame of the driver’s seat, but nothing under the battery.
It’s all coming out tomorrow so I’ll see what happens.
If nothing else it’s saved me paying for a recovery firm to take it 3 miles to the garage.

 

[Craig.]

Have you checked the common power input for SC30 as that fuse supplies a lot of the components that are reporting faults including the trailer module, parking aid, oil sensor?

Also, fuse SC30 and SC32 which basically power everything (including steering angle sensor) that is reporting faults come from relay J329 (Terminal 15 relay) so check that is securely fitted and operating correctly.



That relay feeds power from fuse SC7 which in turn gets its power from SA2 but if there were issues from SA2 then I would expect you would have WAY more faults reported.

So I would be checking relay J329 (should be marked 645) is operating correctly and fitted correctly and then work your way from there.

 

[Craig.]

Next port of call is the common earth point for a lot of, if not all, of the fault reporting units... Earth point 636:



If that is loose then stepping on the centre area would move it as it is located by the airbag control module, which is under the plastic cover under the floor at the bottom of the lower centre console... Sounds like this is where you stepped/worked when the fault changed?

 

[Bigsidavies]

Next port of call is the common earth point for a lot of, if not all, of the fault reporting units... Earth point 636:

View attachment 226809

If that is loose then stepping on the centre area would move it as it is located by the airbag control module, which is under the plastic cover under the floor at the bottom of the lower centre console... Sounds like this is where you stepped/worked when the fault changed?

Thanks Craig. I’m just about to go and make a start. I’ll check in relation to those points as best as I can.

 

[Bigsidavies]

Next port of call is the common earth point for a lot of, if not all, of the fault reporting units... Earth point 636:

View attachment 226809

If that is loose then stepping on the centre area would move it as it is located by the airbag control module, which is under the plastic cover under the floor at the bottom of the lower centre console... Sounds like this is where you stepped/worked when the fault changed?

Well what do you know?
Took the plastic cover off and the earth nut was loose. Waggled the earth wires and all faults came back. Moved them again and they all went and van started.
Tightened the nut down and it took four full 360deg revolutions to get it tight.
Can’t induce the fault again under any circumstances, so hopefully that’s it fixed.
I could have done that 6 weeks ago lol.
Thanks for your detailed explanation Craig and thanks to everyone else who commented with helpful suggestions-some of which did include checking the earth points.
Fingers crossed that’s it sorted.

 

[Craig.]

Not a problem Si, When working I always check the basics first and it's surprising how often the cause of an issue is power or ground.

Nice Dodo you have there too!

 

[n10n]

Well what do you know?
Took the plastic cover off and the earth nut was loose. Waggled the earth wires and all faults came back. Moved them again and they all went and van started.
Tightened the nut down and it took four full 360deg revolutions to get it tight.
Can’t induce the fault again under any circumstances, so hopefully that’s it fixed.
I could have done that 6 weeks ago lol.
Thanks for your detailed explanation Craig and thanks to everyone else who commented with helpful suggestions-some of which did include checking the earth points.
Fingers crossed that’s it sorted.

Congrats! I'm pretty sure that was it.

This is the one earth point that just doesn't make much sense to me - just by moving it 20cm forward they could have it by the gear stick base which would be much more reachable and just as solid metal there as well.

 

[Jollyvan]

That's brilliant news Si. I think we are all relieved that you have found a simple solution. As you say it's a pity you did not find this 6 weeks ago.

 

[drinfinity]

Good to see a resolution to this problem! I’d be tempted to clear all the dodomat away from the earth point so the nut isn’t trying to squish the Dodo as well.

 

[Bigsidavies]

Good to see a resolution to this problem! I’d be tempted to clear all the dodomat away from the earth point so the nut isn’t trying to squish the Dodo as well.

I was pretty sure I’d not put dodo mat under the earth point when I did it, but looking at that pic you could have a point. I’ll sort it before I put the passenger seat back. Thanks.

 

[Bargy62]

@Bigsidavies Looking at the picture the earth point has a dome nut could you not put a hex nut on it with a shallower dome to act as a locking nut save it coming loose again

 

[Bigsidavies]

@Bigsidavies Looking at the picture the earth point has a dome nut could you not put a hex nut on it with a shallower dome to act as a locking nut save it coming loose again

Possibly……….but I’ve just put it all back together now. I’ll do that next time it comes loose.