Best locations to access CAN Bus

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DefenestratorNZ

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Apr 11, 2024
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I have a 2022 leaf and was wondering the best(easiest) places to access the CAN bus.
and are all the CAN buses the Request/Response type or is there some standard broadcast ones I can access?

Due to the incoming Road User Charges for EVs in New Zealand and I would like to keep track of the Odometer and some of the other stats
I have a microcontroller and CAN bus interface. it will log the data and upload once i get home.
 
The OBDII port that is used for diagnostics by the dealer service is a fairly easy place to get access.
 
I have a 2022 leaf and was wondering the best(easiest) places to access the CAN bus.
and are all the CAN buses the Request/Response type or is there some standard broadcast ones I can access?

Due to the incoming Road User Charges for EVs in New Zealand and I would like to keep track of the Odometer and some of the other stats
I have a microcontroller and CAN bus interface. it will log the data and upload once i get home.
Why not just use a commodity OBDII plug and leaf spy pro? Turbo3 has done all this work for you already.
 
Thank you FC that is a good link.
Okay no passive reading anymore--requires active polling by sending request for data, then reading the response. This is how the Consult tool works as defined in SAE J2534, a diagnostics specification and protocol for OBDII Scan Tool and Pass-Thru Programming. You send a data-read request to the ECU of interest, then it responds with the data.

There are likely plenty of high end scan tools that are made to comply with the J2534 standard; in Section 6.1 it involves using a PC with windows XP to talk thru a vehicle communication interface to the OBDII port. There are 9 or 10 "Modes" of operation defined in the spec. Powerful tool for re-programming ECUs also.

Or the gateway can be by-passed with jumper wires to put the CAN Buss traffic back on the OBDII port:
Laef CAN bypass.png

with T-Tap splices
Laef CAN Splices.png
 
Last edited:
Thank you FC that is a good link.
Okay no passive reading anymore--requires active polling by sending request for data, then reading the response. This is how the Consult tool works as defined in SAE J2534, a diagnostics specification and protocol for OBDII Scan Tool and Pass-Thru Programming. You send a data-read request to the ECU of interest, then it responds with the data.

There are likely plenty of high end scan tools that are made to comply with the J2534 standard; in Section 6.1 it involves using a PC with windows XP to talk thru a vehicle communication interface to the OBDII port. There are 9 or 10 "Modes" of operation defined in the spec. Powerful tool for re-programming ECUs also.

Or the gateway can be by-passed with jumper wires to put the CAN Buss traffic back on the OBDII port:
View attachment 3730

with T-Tap splices
View attachment 3731
Cool just what I was looking for
just need to find a good place to splice the correct wires :)
also ill add my thanks to FC for the link

the main item is the Odometer for the RUC but any other data will be entered into our Splunk server for my wife to work with
 
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