How do I connect OBDII cable?

kai · Post by **kai** » Fri Jun 19, 2015 1:34 am

I am new to this, and just got the RaceCapture/Pro 2. I am trying to connect the OBDII-RJ45 cable to it. The cable does power the RaceCapture Pro through OBDII, and correctly shows the voltage is > 14 volts. But all the CAN channel I try to add, such as RPM, Engine Temperature is 0. Do I need to get a CANx unit to plug in between OBDII-RJ45 cable and RaceCapturePro2 RJ45 socket?

Greatly appreciated!!

JMcDonough · Post by **JMcDonough** » Fri Jun 19, 2015 2:29 am

All you should need to do hardware-wise is plug the cable into the car and the RCP.

For RPM, did you write a script to read the correct CAN message for RPM on your car?

Did you try using the built in OBDII PID functionality instead?

What year, make, and model car?

kai · Post by **kai** » Sat Jun 20, 2015 7:44 pm

Thanks for your reply! I am trying to use the built-in function from RaceCapture App like this:
http://www.autosportlabs.net/RaceCapturePro2_OBD2

I tried to add RPM, Engine temperature... etc, and they are all 0, despite I have engine running and can see the RPM is not zero.

My car is 2013 Mercedes C250.

What could be wrong? Is there a boot up sequence (like I need to start the car first before start computer), or it should just plugin and play? Thank you SO MUCH for your help!

JMcDonough · Post by **JMcDonough** » Sat Jun 20, 2015 8:49 pm

Did you write the changes to the unit after you added the signals? (bottom left corner of the app, arrow pointing at the device)

After you write the update, you'll have to reboot the RCP for the changes to take effect. Sometimes I also have to close the app to get the new signals to show up on the dashboard.

Hope this helps!

kai · Post by **kai** » Sat Jun 20, 2015 9:00 pm

Yes I rebooted several times, I have the new signal RPM show up in the dashboard, but it is constantly 0.

I bought the cable from there:
http://www.theracersline.com/products/c ... d-ii-cable

Is it the correct one?

kai · Post by **kai** » Sun Jun 21, 2015 10:47 am

I tried on my friend's car 2015 Porche 911, and it works fine. So it looks like my Mercedes OBD2 connection might be a little different. Thanks for replying my messages!!

Cheers!

Post by **brentp** » Sun Jun 21, 2015 5:47 pm

Hi Kai,

Sorry it didn't work on the 2013 Mercedes. Is this your car that you're testing it on?

Good troubleshooting work on testing on a different car; you've verified at least communications can happen.

Did you try different baud rates on the Mercedes? Typical CAN baud rates are 250, 500 and 1MB.

HangLooseRacing · Post by **HangLooseRacing** » Wed Feb 21, 2018 3:11 pm

Just found this thread so trying to bump it back to life for a quick question. I have an RCP 3 in my Miata and would like to be able to switch it over to the BRZ our team also runs. Looks like you guys have all of the info I could need for can-bus mapping, what I’m wondering is which cable would be the best to purchase. Should I be looking at buying a full spare harness or do I want to go with one of the OBD or RJ plugs?

Thanks.

Post by **brentp** » Wed Feb 21, 2018 3:38 pm

Hi,

You just need this cable for a CAN OBDII connection to RaceCapture/Pro MK2, MK3 or RaceCapture/Track.

https://www.autosportlabs.com/product/c ... -ii-cable/

Thanks!