Help needed with Vehicle Speed message

[aqua_life]

Hi,
I have read OBDII messages in Saturn Vue.
This car has J1850 VPW protocol.
One of the messages I read is:
88 29 18 02 00 00 3A*

This message tells the vehicle speed. And the vehicle was stopped. So speed = 0 km/h.

How can I simulate 10km/h or 20km/h ?
I don´t have car to read messages while running...

I am sure I need to change 00 00 3A but I don´t know how.

Someone can help?

Thanks

[WDZaphod]

What is the idea behind? You like to fake a speed signal for a limiter?
Once the message is on the bus, there is no way to remove it. It's also not possible to block the message. So what is the intention of your question?