Hi

 

Hoping someone could shed some light on what is going on with my octavia

 

Car is a mk3 octy 2.0 tdi estate sel without towbar prep but with acc/Park pilot/Park assist/Front assist etc.. 

 

Had a detachable towbar and dedicated wiring fitted 6wks ago, everything worked fine for a while picke up a trailer and all worked as it should then 3wks ago started getting warnings on the dash

 

ACC and front assist not available

Park pilot not available

Check right rear trailer light

Check left rear trailer light

Long beeping sound from rear of car every 20mins

 

Took it back to the fitters who spent an hour scratching his chin and used a witter handheld thing to reload the software saying it had thrown up a fault

 

Drove away and all was good again.... For just over a week! 

 

Just been out for a drive and all the errors and lights are back but strangely it also auto locked and unlocked the central locking a couple of times

 

The auto locking is a bit of a strange one as I wouldnt have thought that would be part of the systems affected by the trailer wiring and surely the wiring shouldn't affect anything in the car until the trailer is plugged in

 

All these faults happen when nothing is connected and I have had a new battery fitted so that should rule out a battery on its last legs

 

Anyone had any similar issues with witter dedicated wiring? Could it be a dodgy loom or just wired in wrong

 

A

Tried scanning for any fault codes?

 

5 hours ago, Stuart-h said:

Tried scanning for any fault codes?

 

Yeah nothing showing unfortunately

16 hours ago, Cain79 said:

 

Anyone had any similar issues with witter dedicated wiring? Could it be a dodgy loom or just wired in wrong

This has nothing to do with wiring, this is purely a coding issue, I'd kinda guess the writter handheld thing is just downloading a pre-built app based section of code unfortunately, these types of code CAN'T be removed easily as, we don't what's been changed.

 

Best you can do, is get someone with a good understanding of VCDS to return your car back to factory settings then fully code in the towbar in. Sorry it all sounds a bit dramatic but, the correct towbar coding does a lotta things, future owners will expect it to work correctly.

Well that's sounds preferable to stripping out the loom and starting again

 

Probably best not to go back to the fitters with it as they wouldn't be able to return the car to factory settings with their handheld

 

I imagine a stealership would flash the system with a stock file for the car with tow prep which may be my best course of action I suppose

 

Any idea what a dealer would charge for sorting software (ball park fig)?

 

Cheers

 

A

If someone could add to my knowledge by answering the following question then I might be able to speculate on where the problem may lie.

 

Question. - with towbar prep and/or dedicated wiring what is it that tells the vehicle electronics that trailer lighting has been connected i.e. the trailer plug connected and bulbs etc in circuit?

 

Is it a microswitch that makes contact when the plug is inserted (like some towsockets I have had) or does it sense the resistance of the extra bulbs? If the latter it begs the question what will happen with a new caravan/trailer with LED lighting?

2 hours ago, J.R. said:

If someone could add to my knowledge by answering the following question then I might be able to speculate on where the problem may lie.

 

Question. - with towbar prep and/or dedicated wiring what is it that tells the vehicle electronics that trailer lighting has been connected i.e. the trailer plug connected and bulbs etc in circuit?

 

Is it a microswitch that makes contact when the plug is inserted (like some towsockets I have had) or does it sense the resistance of the extra bulbs? If the latter it begs the question what will happen with a new caravan/trailer with LED lighting?

It's the 7th/13th pin

Thanks for the reply.

 

How so? - All 7 are already attributed.

 

I know that in the past I have had a 12N socket with a contact which broke the vehicle rear foglight circuit when the plug was inserted, it had 2 extra terminals behind where the wires were connected.

 

Editted, or does it only work with a 13 pin socket? Perhaps you mean that pins 7 & 13 make a closed circuit when the plug is inserted.

Edited 27 February, 20206 yr by J.R.

46 minutes ago, J.R. said:

Thanks for the reply.

 

How so? - All 7 are already attributed.

 

I know that in the past I have had a 12N socket with a contact which broke the vehicle rear foglight circuit when the plug was inserted, it had 2 extra terminals behind where the wires were connected.

 

Editted, or does it only work with a 13 pin socket? Perhaps you mean that pins 7 & 13 make a closed circuit when the plug is inserted.

Yeah I too would be very interested to know how my car thinks it's attached to a trailer when it's not. I know manwithnoaim says it's just coding but what you say has also made me think, does the car think that it is attached to a trailer due to a short circuit across those pins.. does make sense that It would consider there to be faults with the lights etc because it's not attached to anything

 

Surely that coding only comes into play when the system is told that a trailer has been connected

Exactly my thoughts but I would need to know definitively the "how" before suggesting the "why".

https://caravanchronicles.com/guides/13-pin-socket-basic-fault-finding/

 

Found this - at the bottom of the page it explains how the 13 pin system recognises a trailer. looks like pin 12 is used to create a short between itself and pin 3 (road light earth) when a trailer is connected - so looks like it may be pointing me in the direction of a short circuit/earthing issue

Found this, but it doesn’t give much away..

https://www.rightconnections.co.uk/canbus/

In the distant past on here , I recall an explanation, - using a 7 pin system the system sensed extra resistance and ecu added /cancelled as appropriate

Particular features such as ‘Trailer Stability Programs’ (TSP) are now being introduced and currently installed in nearly ALL new VAG vehicles, BMW X series and the newly produced GM vehicles. The alarming thing about these systems, are that they are a incredibly easy feature to install and activate when towing. With a change to the existing ESP, ( Electronic Stability Program) the vehicle is able to correct a ‘snake’ in a trailer or caravan. These systems are dormant in the software of the vehicle and brought into operation when the car detects a trailer connected.

How does the vehicle know a trailer is connected?

This happens in a number of ways but the most common method is a signal generated by the towing module, which is recognised by the central computer. The signal is sent when a towing plug is inserted into the socket. The vehicle specific ‘Towing Electrics’ can also activate other features associated with towing. For systems such as TSP to operate it is essential to have a towbar wiring kit installation which communicates directly on the CAN bus.

With technology constantly being refined and improved, towing electrics have become as vital as any other electrical system in terms of safety. Therefore, it is CRITICAL to MAKE THE RIGHT CHOICE.

The alternative is to either choose the cheaper universal towing electrics solution or possibly worse, have this chosen for you by a towbar installer. This decision could affect every aspect of the safety of your vehicle and that of other road users.

REMEMBER: Choosing a universal by-pass electric installation WILL NOT allow certain safety systems to function!

 

I ask the question again of those who have paid a lot of money to have what they believe to be a dedicated canbus system fitted and coded to their vehicle after purchase and who then sermonise others saying that they are a danger on the roads, that they might as well be towing with a bungee cord, how do they actually know that their vehicles electronic systems detect that a trailer is fitted and that the ESP etc actually do react any differently and that they dont actually have simply a bypass relay fitted behind the trim panels? All of the posts speaking of the time taken to run a wire to the fusebox are indicative of a bypass relay, a canbus system would have its connections at the rear.

 

Cain, does your vehicle have a 13 pin towing socket? If so then it should be relatively easy to check for any resistance across the two terminals with a multimeter.

Edited 28 February, 20206 yr by J.R.

12 minutes ago, J.R. said:

Particular features such as ‘Trailer Stability Programs’ (TSP) are now being introduced and currently installed in nearly ALL new VAG vehicles, BMW X series and the newly produced GM vehicles. The alarming thing about these systems, are that they are a incredibly easy feature to install and activate when towing. With a change to the existing ESP, ( Electronic Stability Program) the vehicle is able to correct a ‘snake’ in a trailer or caravan. These systems are dormant in the software of the vehicle and brought into operation when the car detects a trailer connected.

How does the vehicle know a trailer is connected?

This happens in a number of ways but the most common method is a signal generated by the towing module, which is recognised by the central computer. The signal is sent when a towing plug is inserted into the socket. The vehicle specific ‘Towing Electrics’ can also activate other features associated with towing. For systems such as TSP to operate it is essential to have a towbar wiring kit installation which communicates directly on the CAN bus.

With technology constantly being refined and improved, towing electrics have become as vital as any other electrical system in terms of safety. Therefore, it is CRITICAL to MAKE THE RIGHT CHOICE.

The alternative is to either choose the cheaper universal towing electrics solution or possibly worse, have this chosen for you by a towbar installer. This decision could affect every aspect of the safety of your vehicle and that of other road users.

REMEMBER: Choosing a universal by-pass electric installation WILL NOT allow certain safety systems to function!

 

I ask the question again of those who have paid a lot of money to have what they believe to be a dedicated canbus system fitted and coded to their vehicle after purchase and who then sermonise others saying that they are a danger on the roads, that they might as well be towing with a bungee cord, how do they actually know that their vehicles electronic systems detect that a trailer is fitted and that the ESP etc actually do react any differently and that they dont actually have simply a bypass relay fitted behind the trim panels? All of the posts speaking of the time taken to run a wire to the fusebox are indicative of a bypass relay, a canbus system would have its connections at the rear.

 

Cain, does your vehicle have a 13 pin towing socket? If so then it should be relatively easy to check for any resistance across the two terminals with a multimeter.

Yes it's got the 13 pin plug so that's going to be my next job when it stops raining - I do think that all my warning lights are coming up because it believes there is a trailer attached due to a short circuit from the 13pin plug 

That was my thoughts, hopefully the connections and seling of the 13 pin plugs are better than the old 7pin type, they really are diabolical and in this weather I would not want there to be any indirect connection with the vehicle electronics and canbus network, they are flaky enough as it is with an electrcal system whose connectors and sealing is light years ahead of trailer sockets & plugs let alone the scabby wiring on the trailer, the toytown light clusters etc.

 

I really do think in hindsight I have done the right thing by using a bypass relay tucked away in the dry.

On 27/02/2020 at 22:44, J.R. said:

Thanks for the reply.

 

How so? - All 7 are already attributed.

 

I know that in the past I have had a 12N socket with a contact which broke the vehicle rear foglight circuit when the plug was inserted, it had 2 extra terminals behind where the wires were connected.

 

Editted, or does it only work with a 13 pin socket? Perhaps you mean that pins 7 & 13 make a closed circuit when the plug is inserted.

I was informed that the 7th or 13th pin (depends if you are using the adapter) making a connection causes the trailer to be detected by the car's canbus. Having seriously, pushed the towing capabilities of my previous 1.4tsi I know exactly how good all the towing software is, I reckon in an emergency, I towed something like 1,650Kg & the car behaved very confidently.

 

I'm not saying tow over weight but, I'm saying the towing software should not be disregarded 

Well I reckon I found the problem! Looks like the fitter attached the earth leads by sticking them down with silicon 🤔

 

Am I right in thinking that's not f*#£ing right.

 

On my way to see them now 

To use a new-to-me acronym that seems appropriate: JTFC!

That's pretty amateur. And lazy because if memory serves me there is a thread to put it on anyway.....

 

But regardless that looks more like bypass wiring, not a dedicated wiring kit. 

I reckon thats what most people actually have when they have paid for what they believe is a "proper job", when they accuse me of reckless endangerment for having fitted my own towbar & electrics (bypass relay), when they spout phrases like "you might just as well tow with a bungy cord" I just smile and visualise what they really have behind the rear trim panels while they believe that they have all manner of sophisticated electronic control systems to save them when the trailer or caravan becomes unstable.

 

FWIW I dont think they are earth wires, there is only usually one and it can be seen on the left although it looks too small a guage conductor, I think its just the fitters way of either creating a common connection or maybe isolating unused cables, its on a par of most wiring I have seen by so called pros in vehicle towbar wiring, ICE or alarm systems.

Well its certainly not a Westfalia electrics kit, I initially thought £150 for the wiring lone was steep but it was very well made. That was on my first scout, second one had a factory towbar. 

 

I agree that because virtually everything is hidden most people won't know what is fitted, which is quite scary, as I bet they often believe they have paid for the full bits. 

I certainly specified dedicated 13pin electrics and not knowing one wiring loom from another I wouldn't be able to say whether what I have fitted is dedicated or not, it's working now so I have use of parking sensors front assist acc etc..

 

When it was working the first time the trailer appeared on the screen when selecting reverse and had lights on the MFD to say I was towing 

 

What would be the difference between a dedicated set up and a bypass relay set up

 

As if I'm missing out on anything important then it would be good to know

I can't find the photos of when I fitted mine but it didn't look like that, far more 'bound' and generally less messy. 

 

In fact I think the only bit that was open wires was the very end that ran into the van-bus behind the glove box. 

 

There are some Google images of the dedicated kits. 

1 hour ago, paddy wagon said:

I can't find the photos of when I fitted mine but it didn't look like that, far more 'bound' and generally less messy. 

 

In fact I think the only bit that was open wires was the very end that ran into the van-bus behind the glove box. 

 

There are some Google images of the dedicated kits. 

Yep doesn't look anything like the westfalia/OEM kit from what I can see so next question is if I've been short changed? and will I be missing out on trailer stability control with a bypass relay? Everything else appears to work as it should