Forum » Off Topic Discussion » C125 dash OBD connection issues

C125 dash OBD connection issues

Off Topic Discussion

Forum Posts



Tech Articles

If it's not really about tuning or wiring. Then it belongs in here.

= Resolved threads

Page 1

Hi everyone,

I've currently installed a C125 MoTec dash into a 2017 Toyota Landcruiser and the idea was to access OBD II data and have it displayed through the dash. It so happens that MoTec have a pre-terminated harness with an OBD II plug which connects straight into the harness and supposedly you're able to access data with no qualms.

I've been having alot of issues with getting this to work correctly, and following the steps supplied by MoTec of OBD II set up, I'm still unable to receive the data. When setting up the OBD II loom, worksheets are preset on CAN 2, with OBDII_Tx as the request and OBD service 01 Reply Comp, as the reply.

The reply is set with compound messaging for all the PID's which include basic data such as RPM, TPS etc. Format is 'Fixed Binary' for both the request and reply with a 500K Baud rate.

I have also tried changing to CAN 1 however the same issues are present. Using MoTec CAN inspector with everything running I am only seeing 'request' CAN ID's. I'm able to plug various OBDII scanners in and read data such as RPM and TPS.

What may be the best way to confirm that the OEM ECU is using the same 'Format/language' ?

Currently I am seeing a 512 value on the CAN 1(as CAN 2 diagnostic channel is set to CAN 1), which I believe is a 'timed out' message? Which confirms no data is being received? Is this correct??

There doesn't appear to be any contact issues as I have continuity from the main dash plug to the OBDII. The CAN wires from the dash are connected to pins 6 and 14 on the OBDII.

Any help would be greatly appreciated!



Attached Files

Have you tried wiring up C125 (with no ODBII can template loaded) and using CAN Inspector while using another ODB-II scanner. That should help you confirm the baud rate is really 500k and not 125k or 1000k.

Hi David,

I tried this morning using an Autel scanner hooked up to the computer via an ethernet cable. However the CAN inspector was unable to pick it up as an available device. I did do a trial and error check with baud rates and found CAN inspector only shows data on 500k.

I also tried loading a new 'default template' into the dash and then manually selecting OBD_Tx and Reply. CAN inspector showed the request but no reply. Also the diagnostic channel is showing '512'.

To be clear CAN Inspector doesn't show any data except what is being transmitted by the dash. That seems odd -- like the baud rate is incorrect.

What I was suggesting is that you figure out how to splice your C125 into the ODB-II CAN wires so that when your Autel Scanner is running you can use CAN Inspector through the C125 to see what is happening on the CAN bus.

I ended up splicing into the CAN wires on the back of the ODB plug. Then tried 2 OBD scanners and used MoTec CAN analyser, which displayed no data at all from either scanner....I tried all different Bitrates through the process but no luck. I did notice when using the Autel scanner, the protocol was labelled at ISO KWP2000? Could it possible the 70 series Landcruiser doesn't use CANBUS for OBD data?

The ISO KWP2000 Protocol can run on either k-line or CAN bus physical layers. I figured that a 2017 would be required to have CAN OBD2 support, but perhaps that not true in all countries.

Autosport Labs make an OBD2 interface that accepts CAN ODB2 requests and uses the correct underlying physical connection (ie. k-line, CAN, etc).

Not sure who sells Autosport Labs products in Australia, you might want to contact directly.

My mistake in the first post it was actually a 2016 model. I managed to get a wiring diagram from Toyota and also to get in contact with Toyota Australia, and through discussions/analysis of the wiring diagrams of each model, it appears the 70 series Land-cruisers from build date August 2016 onward use CANBUS. Because the model I'm working on is July 2016, there is no CANBUS for engine parameters. August 2016 was apparently the 'EURO 5' engine upgrade which included VSC and other VD functions... So the ISO KWP2000 protocol must use K-line?

Is it possible to transfer the data to CANBUS?

The Autosports Labs product I linked to is a device that does exactly that -- allows OBD2 queries on the CAN bus, repeats them to the k-line and returns the result on the CAN bus. I got one to test with, but then sold it before ever trying it myself.

BTW - good investigative work to figure out what was changing in various mid-year model changes!