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Topic: OBD II to set cruise speed (Read 160 times) previous topic - next topic


Hi. I drive a Seat Altea (VW) in Germany. Here speed limits change continuously and I'm becoming obsessed checking tacho after getting a couple of fines (driving 39 and 41km/h with limit 30  :smiley-confuse: ) . This reduces greatly the attention I give to the road.
To ease things I use a lot the cruise control, but with it you just fix the speed when you reach it, and this means to watch the tacho instead of pedestrians. Annoying.

My dream: OBD, arduino and 4 accessible buttons. After activating the cruise speed in the standard way, pushing each button would SET a different cruise speed. I assume the cruise speed is normally written inside a register: I would only change this value.

The hack doesn't activate the cruise speed, but change it when already active.
As soon as I brake the cruise control switches off. From the point of view of security it doesn't change anything.

Is it possible to SET values with ODB or just reading them?
If yes, any idea about where to find "register " maps to know where to write the value?
I know my Seat Altea is Volkswagen compatible because my car is involved in the gas scandal... >:(


From what I've seen the VW vehicles uses CAN BUS on peripheral additions... is your vehicle made in recent years since CAN BUS was implemented?

Have a look at VAG-COM for example.

If so, it may be useful to sniff the CAN BUS pins on the OBD connector to see what communication is sent by the cruise control.

I don't think cruise control is implemented using OBDII though.


Yours is a good idea, but I believe it will not help me.

I imagine I will find commands like "Start cruise with the last saved speed", "Stop cruise", "Erase last saved speed and stop cruise". These are equivalent to some keys I can press while driving.

Alas what I need, "Set cruise speed to X km/h", is not issued by any peripheral in my car, so I cannot sniff it...

The only possibility would be to find a whole map of VW CAN BUS commands with the description of the protocol and the meaning of every register.

Thank you anyway


It seems like nobody has done that before.
Probably there could be a way, but not by official OBD II protocol. It is definitely not part of it!

Some (undocumented) features are individually included on that communication layer.
But especially VW has their very own protocol additionally to that:  VCDS and VAG-Com, which have a higher security layer.

As I read, it is possible to activate the cruise control, if it´s upgraded later on. Activating in the meaning of "making it available". Not setting it up.

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