Accessing can bus with Obdlink MX+ not connected to the obd2 port

Maxmanzo

I'm setting up Racechrono for can bus telemetry but the obd2 port of my car does not expose the can bus and the can wires are on the passenger's side.

My idea is to connect hte MX+ with only 4 wires on the passenger's side (power, ground, can H and can L), skipping the obd2 port altogether.

Obdlink support says it can be possibile, although their app won't work, but advised to confirm with Racechrono.

Looking for advice here. Best, Max

liquidiq

I have the MX+ setup like this on my 911. I’m not currently using RaceChrono but the other software I use it works great. I’ll try RaceChrono today and see how it works with this style of setup.

liquidiq

Yes, works just fine.

Cali_Chuck

Hey @Maxmanzo - yes this works just fine. I have a detailed discussion over on 718forum on how I did this to my Cayman. In fact, for a while I was tied into two CAN buses because I was sniffing CAN signals to try to locate some channels that were not on the main drive CAN.

Detailed photos in this link showing all the hookups all the way to RaceChrono.

https://www.718forum.com/threads/successfully-hacked-my-718-gts-can-bus-for-racechrono-data.31918

Maxmanzo

@Cali_Chuck your post is impressive and exhaustive. I'm folowing the same route but will try to use CanCrocodile instead of Positaps. The only question left is whether to ground both pins 4 and 5 or only 4 in the obd2 connector in order for the MX+ to work.

Cali_Chuck

It's 4 wires. +12V and GND from vehicle as a pair, and CAN H / L as a pair. No 5th pin.

CAN Crocodile requires you to have two powered devices - the OBDLink and the Crocodile. Much simpler to just tap the cable directly.

away_yang

@Cali_Chuck I have the OBDLink MX+ doing exact same on a bimmer, but no data show up in Racechrono. Have you setup anything like initial command specific for CANBUS in RC or just leave everything in default?

Cali_Chuck

I just replied on your main thread.