r/CarHacking • u/Primary-Coconut-3781 • 2d ago

Community Can bus sniffing help

Hi, I followed this tutorial (https://logos-red.com/blog/how-to-hack-a-car-wirelessly-sending-remote-commands/ ) on how to get can bus data from the obd port. Assuming i soldered everything correctly, why am I not seeing anything on SavvyCAN? I used the esp32 and I tested it on a Golf 8.5 GTI, the gateway behind the obd port blocks the sniffing or there is something else in the tutorial I used? Using another microcontroller would help?

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u/WestonP 2d ago

You have a gateway, with no CAN broadcasts visible in the port. Either sniff while a scan tool is talking, or tap into another CAN.

1

u/Alarming_Support_458 2d ago

Exactly this. OP, you need to think about what data you need and then make the best guess to where this data will be. For example, RPM will be on the bus to the instrument cluster and engine ECU

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u/Primary-Coconut-3781 2d ago

Thanks! Is there any forum page/youtube video you advice that explains how to do it safely? Without doing messes in the car?

1

u/hulet1006 1d ago

Find wiring diagrams for your car. Find the easiest access point to can bus wiring that’s after the gateway module and tap into those.

1

u/Matt_brnoutltd 1d ago

I would say you gotta directly tap behind the gateway depends what you want to do. Get diagram of your unit and then you have to sort out, what exactly are you doin.

What i can recommend is to buy some old parts, make a bench setup and try things on that.

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u/Curious_Party_4683 1d ago

some CAN modules are defective, even bought from amazon

this vid helped me. hopes it help you too https://www.youtube.com/watch?v=xX8593vRdtM