[Guide] Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

[Dellmassive]

Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

The T6 is full of ECU`s, Modules, CAN Buses and Data packets . . . . . Just like your Phone or PC right.

The motor vehicle industry has spent years with research and development making the modern car/van Data and electrical system very Robust and resilient with built in redundancies and fail-safe measures everywhere.

But, every now and again things can go side-ways and the electrical gremlins come out to play. . . . . . . This is normally caused by electrical situations outside the normal working parameters for the vehicle. . . .Such as a very low or flat battery, bad starter causing excessive voltage drop, faulty alternator regulator, incorrectly installed solar setup, poor or corroded ground connections etc etc etc,



In the old days just disconnecting the battery terminals was enough . . . .but in modern motors the plethora of protection devices in the modules that does still work . . . . but you have to leave the battery disconnected for (upto) Hours . . . . Why - well most modules have voltage suppression capacitors across the power rails internally that can effectively keep the modules memory half alive. . . . . .for a period of time.

The solution to leaving the battery disconnected over night is whats called a capacitive discharge.

In a nutshell were are disconnecting the electrical system from any source of power and "shorting" the power-supply leads together (The battery cables) to allow the capacitive charge to equalize allowing the modules to fully power-down.

This is what we do . . .

first go find your battery, this will be under the bonnet . . . Note that if you have any other source of power on the van, this must be disconnected too . . . (disconnect the negative terminal from any Leisure battery's you have and isolate any Solar kit your running. Disconnect any EHU obviously too)



Disconnect the Ground cable first . . . . . . . the the positive cable...

Now cover the battery terminals for some added safety . . . a nice Jack Daniels beer Matt will do nicely here . .



Once the terminals are disconnected . . . . we need to get them in a position where we can touch them together (or use a small jumper wire)





next we need to touch them together and hold for 10 seconds.




Then the magic is done and its a case of putting things back together . . . . . .in reverse.

so connect the positive battery lead first this time . . . . . . and lastly the negative. ( you may get a crack or a spark when you do the connection, this is normal due to the inrush of current . . . . . but if you expect it it wont surprise you)

One a side note this can be used to clear any fault codes stored in ECU`s memory . . .so if you haven't got Carista or VCDS you can use this to reset say an airbag light due to taking the passenger side panel off with the ignition on . . . .plus may others.


Remember after disconnection the battery a few services will need resetting, like - Window Pinch (comfort closing) and the radio Time & Date etc etc etc.


Heres some background info from a VW Master tech, now your in-the-know go watch his video:

HumbleMechanic

.

 

[Hopey]

Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

The T6 is full of ECU`s, Modules, CAN Buses and Data packets . . . . . Just like your Phone or PC right.

The motor vehicle industry has spent years with research and development making the modern car/van Data and electrical system very Robust and resilient with built in redundancies and fail-safe measures everywhere.

But, every now and again things can go side-ways and the electrical gremlins come out to play. . . . . . . This is normally caused by electrical situations outside the normal working parameters for the vehicle. . . .Such as a very low or flat battery, bad starter causing excessive voltage drop, faulty alternator regulator, incorrectly installed solar setup, poor or corroded ground connections etc etc etc,

View attachment 46791

In the old days just disconnecting the battery terminals was enough . . . .but in modern motors the plethora of protection devices in the modules that does still work . . . . but you have to leave the battery disconnected for (upto) Hours . . . . Why - well most modules have voltage suppression capacitors across the power rails internally that can effectively keep the modules memory half alive. . . . . .for a period of time.

The solution to leaving the battery disconnected over night is whats called a capacitive discharge.

In a nutshell were are disconnecting the electrical system from any source of power and "shorting" the power-supply leads together (The battery cables) to allow the capacitive charge to equalize allowing the modules to fully power-down.

This is what we do . . .

first go find your battery, this will be under the bonnet . . . Note that if you have any other source of power on the van, this must be disconnected too . . . (disconnect the negative terminal from any Leisure battery's you have and isolate any Solar kit your running. Disconnect any EHU obviously too)

View attachment 46792

Disconnect the Ground cable first . . . . . . . the the positive cable...

Now cover the battery terminals for some added safety . . . a nice Jack Daniels beer Matt will do nicely here . .

View attachment 46793

Once the terminals are disconnected . . . . we need to get them in a position where we can touch them together (or use a small jumper wire)

View attachment 46794



next we need to touch them together and hold for 10 seconds.


View attachment 46795

Then the magic is done and its a case of putting things back together . . . . . .in reverse.

so connect the positive battery lead first this time . . . . . . and lastly the negative. ( you may get a crack or a spark when you do the connection, this is normal due to the inrush of current . . . . . but if you expect it it wont surprise you)

One a side note this can be used to clear any fault codes stored in ECU`s memory . . .so if you haven't got Carista or VCDS you can use this to reset say an airbag light due to taking the passenger side panel off with the ignition on . . . .plus may others.


Remember after disconnection the battery a few services will need resetting, like - Window Pinch (comfort closing) and the radio Time & Date etc etc etc.


Heres some background info from a VW Master tech, now your in-the-know go watch his video:

HumbleMechanic

.

thanks for the info, I will give this a try and let you know.
Cheers

 

[Stigofthedub]

Interesting thread. I would assume the electronics will have other components before the capacitors to regulate the voltage which will apply some resistance to the dead short. Without the detailed drawings I couldn't say.
However if the capacitors were to be directly across the supply leads then dead shorts are not a good idea. The charge disipated by a capacitor will be an instantaneous large current albeit for an instant. This current will generate internal heat and possibly damage. In The industry I was in we would use bleed resistors to limit the short circuit current. I would probably use about 100ohms across the terminals Which would have the same result but without the potential damage.

 

[Epic-Rob]

thanks for the info, I will give this a try and let you know.
Cheers

did it work?

 

[Paul_f]

I am not aware of any ECUs which lose their settings by diaconnecting the power.
All modern ECUs (IE ~2004 and later) would use non volatile memory (eg an EEPROM) that is not affected by power loss

 

[flo.flowers]

After laying the leisure cabling into and under the passenger seat, I laid the cab mat and put the seats back to find the starter battery was flat as the van had been stationary for 4 weeks.
I charged this indoors until at full charge and connected back up to find that I’ve got numerous brake issues displaying not only as warning lights but also on the MFD.
Should I try the ECU reset or douse the issue point to the cabling I’ve disturbed when laying the leisure cable done the centre column?
.shit.
flo

 

[flo.flowers]

It’s a 19 plate T32 @3000 miles.

 

[Pauly]

I would fire it up and drive it then reset any faults and see if any return, flat batteries cause havoc with van systems

Go for the simple options first

 

[flo.flowers]

Cheers Pauly.
Me and the dog went out for about 20 mins in it with nothing seemingly wrong with the brakes lights radio windows, oh, just a n/s indicator bulb at the back which is new.
I’ll try the reset now.
Would any of you know if its likely I’ve interfered with the associated cabling for the brakes, does it travel down the centre then disappear thru’ a hole to under the van?
Regards,
flo

 

[Pauly]

None of that is in the interior AFAIK

 

[flo.flowers]

 

[flo.flowers]

unfortunately after 5 mins of discharge it didn’t clear.
Any ideas welcome...
flo

 

[aramone]

thanks for the info, I will give this a try and let you know.
Cheers

so did this work?

 

[Ambrose]

Discovered that I had a flat battery yesterday (kids been playing and left the lights on), it was so dead that central locking wouldn’t work and nothing happened when I turned the key, so put it to charge over night.

When I came to start it this morning, I did manage to start it first time but the ghost immobiliser kicked in and then had all sorts of beeps going off, and gave out a brake warning - workshop.
Nothing worked so I tried this reset and it worked, the alarm going off when you reconnect the battery scared the life out of me but everything seems to be back to normal working order.

So, many thanks for posting this up, T6 forum saves the day again!

Full Van ECU Reset (Capacitive Discharge) -- How I Done It --

The T6 is full of ECU`s, Modules, CAN Buses and Data packets . . . . . Just like your Phone or PC right.

The motor vehicle industry has spent years with research and development making the modern car/van Data and electrical system very Robust and resilient with built in redundancies and fail-safe measures everywhere.

But, every now and again things can go side-ways and the electrical gremlins come out to play. . . . . . . This is normally caused by electrical situations outside the normal working parameters for the vehicle. . . .Such as a very low or flat battery, bad starter causing excessive voltage drop, faulty alternator regulator, incorrectly installed solar setup, poor or corroded ground connections etc etc etc,

View attachment 46791

In the old days just disconnecting the battery terminals was enough . . . .but in modern motors the plethora of protection devices in the modules that does still work . . . . but you have to leave the battery disconnected for (upto) Hours . . . . Why - well most modules have voltage suppression capacitors across the power rails internally that can effectively keep the modules memory half alive. . . . . .for a period of time.

The solution to leaving the battery disconnected over night is whats called a capacitive discharge.

In a nutshell were are disconnecting the electrical system from any source of power and "shorting" the power-supply leads together (The battery cables) to allow the capacitive charge to equalize allowing the modules to fully power-down.

This is what we do . . .

first go find your battery, this will be under the bonnet . . . Note that if you have any other source of power on the van, this must be disconnected too . . . (disconnect the negative terminal from any Leisure battery's you have and isolate any Solar kit your running. Disconnect any EHU obviously too)

View attachment 46792

Disconnect the Ground cable first . . . . . . . the the positive cable...

Now cover the battery terminals for some added safety . . . a nice Jack Daniels beer Matt will do nicely here . .

View attachment 46793

Once the terminals are disconnected . . . . we need to get them in a position where we can touch them together (or use a small jumper wire)

View attachment 46794



next we need to touch them together and hold for 10 seconds.


View attachment 46795

Then the magic is done and its a case of putting things back together . . . . . .in reverse.

so connect the positive battery lead first this time . . . . . . and lastly the negative. ( you may get a crack or a spark when you do the connection, this is normal due to the inrush of current . . . . . but if you expect it it wont surprise you)

One a side note this can be used to clear any fault codes stored in ECU`s memory . . .so if you haven't got Carista or VCDS you can use this to reset say an airbag light due to taking the passenger side panel off with the ignition on . . . .plus may others.


Remember after disconnection the battery a few services will need resetting, like - Window Pinch (comfort closing) and the radio Time & Date etc etc etc.


Heres some background info from a VW Master tech, now your in-the-know go watch his video:

HumbleMechanic

.

 

[peteaufc]

@Dellmassive I'm planning to do a full van ECU reset, following instructions above in your posts and the voodoo video linked.

My starter battery is connected to a lithium leisure battery, with a ctek switch that I can turn off to stop any flow to positive terminal of my leisure battery. Is it sufficient to turn this off at this switch before I do the cap discharge following the instructions above, or is it essential to disconnect positive and negative cables from the leisure battery as well?

My reason for doing this is to see if it corrects odd behaviour I'm seeing since retrofitting a rear view mirror with HBA - camera is definitely providing input, but only seems to dip beam if I'm going uphill when another car approaches, but not at other times - I'm keen to see if an ECU reset might get things working correctly.

 

[Dellmassive]

if the switch completely disconects the power then that will be fine.

 

[Kind of Blue]

Thank you very much Dellmassive for sharing this with us. While I am at it thank you very much for all your contributions, they are very appreciated!