Multiplexing and technology evolution...

[laraa at sympatico.ca]

Bravo Cody, for this very clear explanation. 

 

I’ll add just a word and it is “multiplexing”. That’s the name of that technology and it is everywhere now. And because of this, cars are “simpler” mechanically now. The ABS wheel speed sensors are used for the speedo and the cruise control, while an common air temp sensor is used by A/C, engine management and the IC temp display. Without multiplexing, you would need a very complex wiring loom with relays and diodes and switches for a single sensor to feed an  analog signal to numerous devices.

 

Last word about technology evolution. A few weeks ago, I drove a new 2015 Nissan Micra as a press vehicle. This one is the cheapest new car for sale in Canada : 9998$. For that, no AC or electric windows or even a remote for the trunk. All manual locks. And then, my 9 yr old daughter told me it was her favorite car for a very simple reason. Instead of having a finicky touch pad or a hidden button to open the trunk, it is an old-style black grab handle, very intuitive and easy to use. More, the hatch is so light she can swing it up easily without fear of crashing it on her head. 

 

When was it that we decide all “user interfaces” needed to be electronic ? 

 

Louis-Alain

 

 

 

De : Cody Forbes [mailto:cody at 5000tq.com] 
Envoyé : 22 février 2015 09:46
À : <laraa at sympatico.ca>
Cc : Tihol Tiholov; <quattro at audifans.com>
Objet : Re: quattro Digest, Vol 136, Issue 18

 

Guys, as a professional working on newer cars, this isn't something unique to anybody. Every manufacturer except maybe TaTa requires module programming from expensive sources. Some make it easier, some make it harder, but none make it free. There's an SAE standard J2534 for programming emissions related components, but beyond that you've got to have very high end tools and paid subscriptions to do anything. By law "Theft related parts" are NOT required to be sold. Mercedes, for example, takes that to the extreme; you may not purchase an ignition switch from Mercedes. They will only install and program them at the dealer and only with the owner present with two forms of ID (this can be fudged by having a good relationship with the local dealer). Merc takes it to the extreme by also denying sales of window regulators and door handles, and more) under the TRP guise. 

 

My point is that this story isn't an Audi thing, it's a current era of cars thing. Ignition switches are no longer "switches". They are a network controller. They don't turn power circuits on and off, they send a command across the network to a power controller which turns on some circuits. Other devices just get constant power and turn themselves on via network command. This eliminates LOTS of wiring. Complicated devices like a drivers side window switch assembly that used to have 10+ large gauge wires to switch power to four windows now only need 4 teensy wires: power, ground, and network. Pulling the switch to make a window go up doesn't switch power, it merely sends a command to the window motors control unit to tell it to go up. This is the standard everywhere from Audi to Honda to Zonda.

 

One thing I tell customers in these situations is that you have to remember that while your $75,000 Audi has depreciated to the $30,000 that let you afford to buy it, you must remember that new parts do not depreciate and still are sold for a $75,000 car. 10 years down the road when it's a $10,000 car on its 3rd+ owner the parts still were made for a $75,000 car and will still be priced accordingly [This is a made up numbers example, not referring to this exact situation ;-) ]

 

J2534 - http://www.boschdiagnostics.com/testequipment/diagnostics/j2534/Pages/J2534FAQs.aspx

-Cody Forbes (mobile)


On Feb 22, 2015, at 12:06 AM, <laraa at sympatico.ca> <laraa at sympatico.ca> wrote:


Holy crap!  Occasionally I have an urge to get another Audi. But posts like



this remind me why I sold my last one and haven’t gotten another.

 

May your A6 now treat you as well as you treat it.

 

—

Kent McLean





Sounds like part of the anti theft immobilizer system. Any recent vehicle will be subject to these kinds of issues.


AFAIK or remember reading, VAG products 2004+ need this reprogramming of certain modules, done only at dealerships by the car talking directly to HQ. Not sure, if all brands or all markets. It's why I'm eyeing Audi Avants up to 2003 MY.

Tihol



Saab's 9-3s (2003-10) and last gen 9-5s (2010-11) are like that. But an indy can reprogram the car if he has a temporary access to GM's database (20$ per day). The shop will obviously need an appropriate GM scan tool, called Tech2, with the Saab software.

Louis-Alain

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