TCU CAN-BUS discussion

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Joined: 23 Oct 2021, 00:18

TCU CAN-BUS discussion

Post by kjn »

I've found the public documentation of the TCU CAN I/O a little lacking.
I thought I would start a discussion based on the current firmware level for those who are chasing more information (like me).

Information is from firmware v10_54
Anything italicised is a question yet to be answered

What is the CAN Bus setup on the TCU?
Two programable baud rate CAN busses. Limited configuration options as follows:
CAN1: CAN-BUS Gear Selector Only?
CAN2: ECU communication (OEM and Aftermarket), Custom Logging Channels (CSB V3 - Analog and Statuses ), Wheel Speed?

What ECUs are supported?
  • EMU Data Stream
  • MoTeC M1
  • TCU Standard Can
  • Haltech IO Expander Emulation
  • BMW 6hp Exx
  • BMW E46,E39
  • BMW FXX**
  • Nissan 350Z**
  • Merc AMG55 5-G
  • Chevy Camaro SS
  • Trailblazer, Saab 97X
**is read only (sensor into TCU) - TCU cannot transmit torque requests?

What internal TCU Sensor channels can be accepted from ECU over CAN?
The following can be configured in TunerPro: MAP, TPS, DBW, Program Switch, Gear Selector, Footbrake, RPM.
How to configure is likely dependent on the ECU selected, clarification required.
It appears it can also accept engine CAN losses and current engine torque over CAN - not documented.
Presumably these depend on the available CAN templates for the ECU? TBC anyone have a list of supported channels for each ECU

It it possible to Tx/Rx Torque values over CAN?
It would seem that this is supported for some OEM ECU's but the exact details are not exactly clear.
TunerPro indicates sources "CAN TQ1, CAN TQ2 and CAN TQ3" are available as CAN input.

Additionally for torque requests:
CSB V3 ID+2 - Byte4.0 is a flag for a torque reduction request.
and the following channels can be attributed to CSB V3 ID+0 or ID+1
17 - Torque Reduction Table to Voltage
18 - Torque Reduction Table to Voltage Inverted

How does Wheel Speed over CAN work
Currently unclear, clarification would be good. There is a base id setting but no other details

How does "Custom ECU" (EMU/MegaSquirt) CAN work?
Currently unclear, clarification would be good.

What does "Can2 Send Data Enable" option do?
Currently unclear, clarification would be good.

What does "Enable Send 8gear Can2" option do?
Currently unclear, clarification would be good.

For my current project I would really like to clarify the "TCU Standard Can" ECU templates look like.
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