Heater Support Pump and Voltage error woes

[T6_FunBus]

Bit of a dogs dinner but made some temporary connection, a solid 12v supply and ground now, and its throwing the same static error ‘supply voltage’. 12v going in is solid at the connector.

On the ecu wire the voltage goes up to about 10, the drops to zero then recovers again every few seconds. Is this supposed to happen?

 

[T6_FunBus]

The soldered joint snapped, so maybe it wasn’t good when I did it yesterday…

I’ve managed to expose a small stub of the remaining wire, and connected it along with the new power and ground to the pump. No fault yet, I guess I will leave it running for 10-15 mins and see if it returns.

 

[T6_FunBus]

Ran the pump with ignition on and temporary wire twisted on the end of the purple blue wire and not fault has returned. Cycled ignition a few times. So assume the soldered wire was a bad repair.

Need to try and work out how to get some more of the blue wire, maybe I will try to crimp connection this time /shrugs.

Still running on new power and ground, but, given the error still kept coming back, I’m guessing okd power / ground is OK, and so just need to renew blue and purple.

Still not conclusive though until repaired and tested.

 

[T6_FunBus]

Tested old connector but with a temporary wire looping the broken wire together. Ran for 20 mins no pump errors.

Pump speed was fluctuating a lot more though? When it has static voltage error it seemed to constantly run full speed? I did also noticed when ECU wire disconnected it just ran full speed too, so maybe it is supposed to speed up and slow down when ECU is controlling it and properly connected??

It was odd as it sounded to me like it was worse now when it keeps slowing down and speeding up!



I decided to cut the wire shorter, soldered and then wrapped. Finally put a sleeve over it and cable tied.



I haven’t had chance to put the airbox, pipe and other sensors back. But hope to do that later.

Really hope this sorts it out and I can be error free.

 

[T6_FunBus]

Put it all back together, cleared errors and all looking good. Ignition on, let the pump run for 10 mins annnnnnnnnd……

Fault came back…

Well that’s a waste of two afternoons and a weekend, cancelled my plans to attack this, caused a row with the missus and back to square one.

Either I am appalling at repairing wires or, it wasn’t just the ECU wire that is faulty, or they didn’t change the pump and just wiped it off, or, they put the wrong pump on, or, or, or.

When I had a fresh live, and a fresh neutral and connected to that existing stripped ecu wire I ran that thing for 30 mins and cycled ignition and it was fine. When I repaired the wire, joined it to the old plug and used old live and neutral, I ran it for about 20 minutes and it was fine.

As soon as I put the air box back in and it all back together and try again - static error on heater support pump supply voltage.

I’ve had this problem for 6 months now. I’ve thrown countless hours at it, and even attempted to get garages to fix it. I am so done.

I’ve got no time or energy left atm to attempt to fix it right now.

I think the only option now is to bypass all the existing wiring with a new loom and use a new plug to the pump. But no clue when I’ll be able to get around to it, and tbh, lost all confidence in me being able to do it, as clearly I suck at fixing wiring and electrical issues (much like my local garage I guess).

Signing off for the night. A thoroughly fed up and emotionally drained T6 owner.

 

[T6_FunBus]

I attacked it today, fed a new power and ground with a new plug to the pump, but, using the old repaired ecu wire - same issue.

So I’ve got to the ECU and the connector I need, almost certain it’s actually the blue pink one on top, but I need to be sure.

On my Audi this cover just slid off - doesn’t seem to want to move on the transporter, how do I unclip / slide it off?



The connector does it then pull out and slide apart to access pins / see no’s?

Also, I have noticed water in the bottom of the battery tray and on the outside of the ECU, there is some in the main box, where could this be coming from? I’ve dried it all out but want to make sure water does not get back in.

Thanks.

 

[T6_FunBus]

New ECU wire from ebox
New Power from fused spur on sb29 from fuse box
New ground
New plug
New pump
Same problem

This is haunting the absolute hell out of me.

Stressed out beyond belief over it. No idea where to turn next.

 

[mmi]

New pump

Is it OEM part?

 

[CJW]

Also, I have noticed water in the bottom of the battery tray

The scuttle has a drain point that is quite close to the battery tray. Is it clear of obstructions? Mine was full of seeds and leaves from a nearby tree. And sludge.

I’ll see if I can find a photo.

 

[T6_FunBus]

Is it OEM part?

It is indeed



Garage said they only get the pumps from the main dealer, as pattern ones usually give errors.

 

[CJW]

The scuttle has a drain point that is quite close to the battery tray. Is it clear of obstructions? Mine was full of seeds and leaves from a nearby tree. And sludge.

I’ll see if I can find a photo.

Can’t find my photo but here is a similar situation:

Hey guys,
Hope you’re all well. Just wondering if anyone can ease my mind and confirm if this is an unavoidable problem. Noticed a small leak in the passenger footwell of my 2017 T6 transporter (second image). Pulled the glove box off and found no real damp spots. Pulled the scuttle panel off, cleaned the leaves and noticed that one of the cables running from the scuttle recess to behind the battery was damp. Checked the rest of the battery compartment and the material mat the battery is mounted to is saturated. The rain has been absolutely torrential in Australia (100mm a day and van parked outside) at the moment so I figured this is something to be expected. Can someone please confirm if this is unavoidable and a non issue before I start pulling more things apart?

View attachment 147622

View attachment 147623

View attachment 147624

My van had about 160k on it when I cleared the scuttle out. Was quite a job and very easy to imagine a little more debris would have stopped draining properly. The battery area was grimy. After a dam good clean of the scuttle the battery area has stayed clean too.

 

[T6_FunBus]

Can’t find my photo but here is a similar situation:

My van had about 160k on it when I cleared the scuttle out. Was quite a job and very easy to imagine a little more debris would have stopped draining properly. The battery area was grimy. After a dam good clean of the scuttle the battery area has stayed clean too.

Thanks, it’s not flooded in there just some damp / wet around the bottom of the e-box.

When I disconnected the ecu, the pins etc and inside the connector were ok.

Haven’t noticed any water or damp in the cab, and I’ve had the floor up to wire in split charge and amp before etc. But I’ve never checked the scuttle drains so will have a look thanks.

 

[T6_FunBus]

I’ve given up for now again.

Spent probably 4 hours this morning removing everything and splicing a new wire into the heater pump ecu wire, putting it all back, and routing it round the back of the engine bay.

Tested with new plug, ground, ecu wire and positive from sb29 fuse in fuse box, and it seemed ok (ran for 10 mins).

Decided to try old plug, with original live, ground, but new ecu wire spliced into it. Error returned within 5 mins.

Went back to new plug and all new connections, error returned within 5 mins.

So to keep it all tidy, I’ve just put it back to how it was on the old loom / connector with the only addition the new ecu wire on the old connector, so original power, ground but new ecu wire.

Cleared codes and ran again - no errors.

I’m sure it’ll be back though. For now, I’m just going to use the damn thing and wait and see if the EML comes on or not.

If it does, then I guess I’ll need to find someone recommended on here to take over and have a look. But, it’s got a new pump and I tried new wiring, unless by some really bad luck, the second ecu wire I installed is crap.

I also tried running the pump direct from a 12v fused battery feed on the positive battery terminal direct - same error ‘supply voltage’.

I crimped the connection on the ecu wire, so maybe, it doesn’t like a crimped connection, but the two wire were joined then crimped. I could have soldered, but idk, seemed like a solid connection then wrapped with Tesa loom tape. I then routed the wire through the rubber grommet on the side of the ebox, and sleeved it to protect it. Routed it round the back of the battery and firewall and master cylinder the down back of airbox and connected into the pump.

At the pump end I stripped three times for fresh wire, I tried solder connection, just twisted and crimped at the pump connector just in case either method was crap.

The 12v according to my volt meter is solid, and ground ok on both methods (old loom and new). I used .5mm wire for ecu, live and ground, same as was there originally.

The only thing I can see by using voltmeter as the output / ecu control wire is it shows about 9v ish, and drops to zero then goes back up periodically as the pump cuts in and out, assume this is normal behaviour on the control wire?

That’s it for now. No more ideas.

 

[T6_FunBus]

This appears to be the part they fitted 5Q0965561B, at least it looks like it from the last part of the part no I can see.

Transporter T6 2016-2019 Water Pump EGR System | 5Q0965561B

| Transporter T6 2016-2019 Water Pump EGR System | 5Q0965561B | Genuine VW Parts and Accessories

vwvanpartsdirect.co.uk

 

[Craig.]

Hi bud,

Assuming the wiring changes you've made are good then here are potential causes that I have encountered first hand so whilst unlikely, they can happen:

1. ECU has developed an internal fault
2. Pin internals have separated at one of the plugs
3. Pump is FOA

When wiring has been changed replaced to the point where the wiring isn't suspected anymore then it falls to something at the end of the wires. So either pins or components.

 

[Craig.]

I think the only option now is to bypass all the existing wiring with a new loom and use a new plug to the pump. But no clue when I’ll be able to get around to it, and tbh, lost all confidence in me being able to do it, as clearly I suck at fixing wiring and electrical issues (much like my local garage I guess).

My offer of making a bypass loom is still available. I may even have a plug here so it will be less fiddly and no need to unpin any plugs. You can tap it onto the ECU wire at the unsheathed wiring at the ECU plug so it'll rule out the ECU wire altogether.

 

[T6_FunBus]

Thanks. Not sure really where to go then, as I don’t know the pump they fitted isn’t faulty, so to ask them to fit another is just me guessing, so I am sure they won’t cover the cost. Not sure how to get around that? It’d be another £300 plus bill to perhaps only discover it wasn’t the pump again.

I probably need someone who can test the ecu signal wire with proper kit? As I only have a volt meter. Not sure how the pump can be tested, as it clearly powers up and runs, so idk how I could prove the pumps circuit board or whatever is at fault as is.

I looked at the end of the ecu connector, after a bit of a fight getting the purple locking tab back in, it looked as though all pins were seated ok, although some did look a bit wonky compared to others.

I guess to test the pump theory I maybe need a known good one to connect outside the system to see if the fault returns or not? Assume it shouldn’t do any damage if ran with ignition on only (engine not running)? Is that an idea? Although where would I get a known good pump from to test :/

I can pull the battery out and check the wire didn’t get snagged behind the battery, I put it in one of those hard plastic corrugated sleeves to protect it. The battery install did squash the casing a bit in the corner where it comes out, but I checked and it didn’t look anywhere near enough to actually crush the one small wire inside.

I didn’t fit an entirely new wire with new pin in the connector, I assumed the wire at the ECU end was not the problem as it was not broken and did not look worn.

All this time when I was testing at the weekend, I could clear the error, where it would not come back for several mins or perhaps until a start cycle and engine running. It was not present 100% of the time. So seems to be an intermittent fault.

But it looks like once it appears as a static error, priority 2 once, it will not go by itself back to intermittent and must be cleared.

If it was the ECU, would we not expect other faults to crop up?

I’m just getting tired of it now, spent about £500 and two whole weekends on this problem, and seem to still be no further forward :/

 

[Craig.]

Here is the ECU pin layout. You want the (smaller) left 60 pin plug, pin 43. On the diagram, it's 3rd pin from the right, second row from the top. From that, you should be able to work out which pin it is.

The plug does come apart, they're just fiddly.

 

[Craig.]

Thanks. Not sure really where to go then, as I don’t know the pump they fitted isn’t faulty, so to ask them to fit another is just me guessing, so I am sure they won’t cover the cost. Not sure how to get around that? It’d be another £300 plus bill to perhaps only discover it wasn’t the pump again.

I probably need someone who can test the ecu signal wire with proper kit? As I only have a volt meter. Not sure how the pump can be tested, as it clearly powers up and runs, so idk how I could prove the pumps circuit board or whatever is at fault as is.

I looked at the end of the ecu connector, after a bit of a fight getting the purple locking tab back in, it looked as though all pins were seated ok, although some did look a bit wonky compared to others.

I guess to test the pump theory I maybe need a known good one to connect outside the system to see if the fault returns or not? Assume it shouldn’t do any damage if ran with ignition on only (engine not running)? Is that an idea? Although where would I get a known good pump from to test :/

I can pull the battery out and check the wire didn’t get snagged behind the battery, I put it in one of those hard plastic corrugated sleeves to protect it. The battery install did squash the casing a bit in the corner where it comes out, but I checked and it didn’t look anywhere near enough to actually crush the one small wire inside.

I didn’t fit an entirely new wire with new pin in the connector, I assumed the wire at the ECU end was not the problem as it was not broken and did not look worn.

All this time when I was testing at the weekend, I could clear the error, where it would not come back for several mins or perhaps until a start cycle and engine running. It was not present 100% of the time. So seems to be an intermittent fault.

But it looks like once it appears as a static error, priority 2 once, it will not go by itself back to intermittent and must be cleared.

If it was the ECU, would we not expect other faults to crop up?

I’m just getting tired of it now, spent about £500 and two whole weekends on this problem, and seem to still be no further forward :/

With ECU faults, it can be a singular issues or a flood of faults and anything between. Which is frustrating!

If the ECU connector looks good and no green/corrosion evidence at all then I'd wager the ECU connector is fine.

With the pin becoming separated, that can present as an intermittent issue. Had that a handful of times, including on a 6 month old Passat that the dealership couldn't find. It kept losing functions for things on the column like wipers, horn etc, turned out the earth loom from the plug on the column had the pin separate inside the plug. Replaced that and it was good until the owner sold the car 3 years later.

 

[T6_FunBus]

My offer of making a bypass loom is still available. I may even have a plug here so it will be less fiddly and no need to unpin any plugs. You can tap it onto the ECU wire at the unsheathed wiring at the ECU plug so it'll rule out the ECU wire altogether.

Thanks Craig, it might be worth it? Although I already ran a new .5mm wire from the ecu (I cut then spliced the purple blue wire about three inches behind the ecu pin into the new wire, assuming the splice was good). I’ve already tried a new plug (it was just an generic vw 3 pin style connector jobbie with sliding grey tab, wires already attached, but fits fine) and then joined new power wire to fuse box, new ground to a bolt under the bonnet to chassis, and then that ecu wire to the three wires that came on the plug in the correct order, and got exactly the same result /shrugs.

I could try it all again with another loom, but not sure if it will just result in the same?