Shorting battery cables (not battery itself!) to clear error codes

[dss123]

Hey...

I had the dreaded glow plug / engine management and emission control / Engine management lights come on during a journey at the weekend.

The van went into limp mode. I wasn't limited on revs and could still get to a reasonable speed... but was very down on power. Like no turbo.

I fully intend to take to the garage as the van (second hand) is still under warranty. But I wanted to read the error code myself first so have ordered a Carly OBD Scanner.

Looks like it may take a while to arrive though, so a mate has suggested disconnecting the battery cables and shorting them together for a few minutes to reset everything.

Is this a good idea? Or should I leave alone until I can get the error scanned?


Another (possibly totally unrelated) observation was that the lights came on immediately after I had crossed the most violent set of dual carriageway rubble strips I have ever experienced! Lots of very heavy vibrations.... then the lights came on. So I'm wondering if a sensor, plug, pipe was shaken loose?

I also recall getting a message on the dash saying "Auto Start / Stop fault".....

I need to get it scanned of course..... but wondered if the battery cables trick was something worth trying in the interim.

Cheers


Dunc

 

[whodat]

I would think that is a great way to destroy the battery.
Any clues as to what van you've got, or is it a bit of a secret?

 

[Dellmassive]

More info.

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

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...

www.t6forum.com

.

 

[whodat]

Really?
I stand corrected. After seeing what happens when a spanner touches both terminals, I wouldn't have thought that was a good idea.

 

[Dellmassive]

Really?
I stand corrected. After seeing what happens when a spanner touches both terminals, I wouldn't have thought that was a good idea.

No.. read the post again.

100% NOT THE BATTERY TERMINALS !!!


...


IT'S THE VAN SIDES CABLES THAT ARE TOUCHED TOGETHER.... WATCH THE VID.

 

[TallPaul_S]

Really?
I stand corrected. After seeing what happens when a spanner touches both terminals, I wouldn't have thought that was a good idea.

Connecting the van cables together when they're disconnected from the battery is a VERY different thing from connecting the battery terminals together.

The latter is (obviously) not recommended. The former fine, as per @Dellmassive post.

 

[dss123]

I would think that is a great way to destroy the battery.
Any clues as to what van you've got, or is it a bit of a secret?

No.. just shorting the cables... once disconnected from the battery. i.e. no power to the van except any residual charge left in the various electronic circuits.


Van is a T6 2.0 Highline. 2019

 

[dss123]

More info.

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

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...

www.t6forum.com

.

Thanks Dellmassive....

I'm assuming this will clear the error code.... though if there is actually a fault with my van, it will just return again.

I'm also wondering if this will clear any record of the fault? In other words, when I connect my Carly (when it turns up) will there be any record of the fault on the ECU or will that be gone for good?

I'm just wondering if it's worth waiting to get the fault read before I clear it?

Cheers


Dunc

 

[Howzat]

I dont think shorting clears codes but to be honest I've never tried because I use the OBD scanner for that. If you do short let us know if the codes clear.

 

[roadtripper]

Draining the power using this technique is not so much about clearing codes but clearing odd running states in the various ECUs (which may be exhibited as odd behaviour or codes that keep coming back once cleared) by ensuring everything does a cold start. Normally the ECUs just enter deep sleep states and never truly reboot.

Be warned after doing it things can be in an odd state for a while because the boot order of the ECUs isn't guaranteed so they can take a bit to sort themselves out - don't panic

 

[dss123]

Draining the power using this technique is not so much about clearing codes but clearing odd running states in the various ECUs (which may be exhibited as odd behaviour or codes that keep coming back once cleared) by ensuring everything does a cold start. Normally the ECUs just enter deep sleep states and never truly reboot.

Be warned after doing it things can be in an odd state for a while because the boot order of the ECUs isn't guaranteed so they can take a bit to sort themselves out - don't panic

Thank you and yes…. I’ve shorted the cables… also charged the battery, but the glow plug light is still flashing and the engine management light is still on. So it’s not cleared anything.

So I guess I’m just going to have to wait until I can get it scanned.

I’m also getting an “Auto start stop” error on startup… so I don’t know if that is indicative of a particular fault??

Cheers

Dunc

 

[roadtripper]

Codes first, restart second

Carista is a good option for a one off VW specific tool, there is OBD11 and VCDS too.

If you get the list of modules with errors then it might also be worth taking out VIP Membership to get access to the wiring diagrams. If there are seemingly unconnected faults you may find common wiring points between them. Don't forget to check the grounds as well - there was a long running investigation that eventually found a loose ground nut.

 

[dss123]

Codes first, restart second

Carista is a good option for a one off VW specific tool, there is OBD11 and VCDS too.

If you get the list of modules with errors then it might also be worth taking out VIP Membership to get access to the wiring diagrams. If there are seemingly unconnected faults you may find common wiring points between them. Don't forget to check the grounds as well - there was a long running investigation that eventually found a loose ground nut.

Thanks Roadtripper - That's really helpful.

I did look at Carista... but actually ended up ordering a Carly, which is hopefully due to arrive soon. Apparently this lets you dive a bit deeper into the fault code and offers advise on what the actual fault might be.... so we'll see.

I am wondering if something has shaken loose as the fault did seem to come on after hit a violent stretch of rumble strips!

Cheers