# 00470 error code



## chirs1211 (Nov 22, 2019)

Just scanned with Carista and got a 00470 code something about canbus in single wire mode.
From what i gather canbus should be using 2 wires, is that right?
Can anyone shed some light on this as i've no clue what it means for the car, as everything works fine, or where and how to find the fault and fix it .

Thanks

Chris


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## IPG3.6 (Sep 5, 2015)

Have you installed something recently, worked somewhere recently or played with something where wiring got disturbed??

If you auto scan the car it might tell you which module is working in single can mode.


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## chirs1211 (Nov 22, 2019)

Nope i haven't done anything to the car, wouldn't have found this if i hadn't need to reset the service light. 
The Carista is a pretty simple OBD2, which was all i needed at the time, & i don't get any OBD2 errors it just says- 
CAN network gateway- 00470- Combination comfort Databus in single wire.
That's it, & if you click on it it sends you to google to search.

From what i managed to find, which isn't much, the CAN-bus should operate via 2 wires so this indicates one is damaged, but it was fairly general info and not vehicle specific so i'm unsure how applicable it is.

I'm going to email a few local auto electricians as well and see what comes back.

Chris


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## SwissJetPilot (Apr 27, 2014)

Did you do a Google search for "Ross Tech XXXXX" where XXXXX is the fault code? They may have a suggestion.


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## chirs1211 (Nov 22, 2019)

I did yes...
http://wiki.ross-tech.com/wiki/index.php/00470

Not exactly tons of info and i'm afraid what is there means nothing to me :? Any light that can be shed would be appreciated. Doesn't say why it's in single wire mode, & how many wires should there be?
Whats a MVB ? Where is it and where are these modules they're on about? [smiley=bomb.gif]

Safe option i guess i an auto electrician.

But my main worry is what is it, what does it do, is it going to cause problems and the implications of this single wire mode.
At the moment everything works as it should

Chris


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## John949 (Apr 12, 2017)

The detailed answer to your question is quite complicated and you'll need some electronics knowledge to understand it. Basically it is a cheaper and simpler way to operate the CAN bus (at low speed) and some components are designed to work that way. This means that "single wire operation" is not necessarily a fault at all it just means that at least one component on the bus has been designed with a cheap CAN interface. I have seen this "fault" on quite a few cars before and I have never worried about it.

Having said that it can sometimes be indicative of a fault as it can also be used as a fallback mode in the event of a failure. If it occurs on one of the high speed buses (powertrain and diagnostics) then it is definitely a real fault.


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## chirs1211 (Nov 22, 2019)

John949 said:


> The detailed answer to your question is quite complicated and you'll need some electronics knowledge to understand it. Basically it is a cheaper and simpler way to operate the CAN bus (at low speed) and some components are designed to work that way. This means that "single wire operation" is not necessarily a fault at all it just means that at least one component on the bus has been designed with a cheap CAN interface. I have seen this "fault" on quite a few cars before and I have never worried about it.
> 
> Having said that it can sometimes be indicative of a fault as it can also be used as a fallback mode in the event of a failure. If it occurs on one of the high speed buses (powertrain and diagnostics) then it is definitely a real fault.


Thanks John,appreciate the explanation. So basically it could be perfectly normal, which i'm hoping for as everything is working fine, or just wait until something goes pear shaped  
Don't really see much point going to an electrician then to just waste money to try and find a 'fault' that may or may not even be there.
So it'll be fingers crossed hope for the best and wait and see.

Thank you for all the responses guys, must appreciated 

Chris


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## John949 (Apr 12, 2017)

Sorry all, talking *******s again. I misunderstood the description I read.

There is a good explanation of how the Audi CAN buses work here:

https://procarmanuals.com/vag-ssp-97160 ... hnologies/

I've been digging into this because my CAN sniffer is not working reliably and it turns out that it shouldn't work at all on the low speed buses. There are some systems that are designed to use CAN over a single wire. These are known as SWCAN systems. However the Audi Info & Comfort buses are designed to be two wire CAN buses that can work in single wire mode if one of the wires is disconnected.

So ignore my previous comments! I now believe that single wire operation is a real fault and means there is a continuity break in either the CAN L or CAN H wire somewhere in the circuit. To find it you would need to check continuity between the pins on each component on the bus. This is potentially a lot of work so you might just decide to live with it.

If anyone is interested: on a 'normal' CAN bus CAN H & CAN L idle at te same voltage (about 2.5V) on the Info & Comfort buses CAN H idles at 0V and CAN L idles at 5V (yes I have got that the right way round). The Powertrain and Diagnostics busses are int their Dominant state (logic 0) when CAN H - CAN L > +2.2V and the Info and Comfort buses are in their Dominant state when Either CAN H > 3.5 OR CAN L < 1.4 V. By referencing the bus to earth it can work on a single wire, whereas the high speed buses are only refernced to each other - hence you need both.

My problem is that most CAN interfaces (e.g. Arduino CAN shields) are designed to work on high speed buses and usually have a resistance of about 50 Ohms between CAN H & CAN L (this is the recommended termination resistor for a CAN bus). If you connect one of these, to say the Info bus, it pulls the votlages close together and the voltage swing may not be enough to trigger the comparators - in effect it shorts out the bus. The annoying thing is that I have had it working fairly reliably like this, but I have now re-wired it neatly and it won't work at all.


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## chirs1211 (Nov 22, 2019)

Thanks for looking into this further, if i remember correctly in was either in the infotainment or convenience CAN i had the single wire 00470 code on, i'd have to re-scan to be sure, i'll do it again tomorrow. At the moment all is working perfectly, so i think i'm going to have to live with it for now or until it's not. At least it not a critical system.
I'm guessing only Audi dealers will have the specific equipment to source the fault? So likely £££ [smiley=bigcry.gif]

Chris

*EDIT* Kinda remembered incorrectly, the error was 'CAN network gateway- 00470- Combination comfort Databus in single wire' so not sure which canbus this relates to, all a bit over my head i'm afraid. No other errors showing though.


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