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CAN Lambda connection issues - R53 MINI G4+


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Thanks in advance for taking the time to read this; this is my first endeavor into standalone ecu stuff so it shouldn't be a surprise that even after weeks of research i'm still running into problems.

Following the setup instructions in the installation manual, I get "device not detected" when searching on CAN 1 - CAN 2 on the R53 is used for the factory cluster and other stuffs

At the Deutsch connector to the CAN Lambda module:

12 volt = 12.80v; CAN Low = 0.20v; CAN High = 1.20v; Ground is good. 12 volt is wired according to recommended diagram in installation manual

Measuring across the CAN pins in the connector, i get an even 60 ohms.

CAN1 Errors: Acknowledge Error, Error Passive, Bus Warning
Transmit Error Counter: 136
CAN DIG #1 State = ON


Attached is the base configuration file from PCLink with my attempted CAN setup per the provided instructions.



BMW Mini R53 G4+ Xtreme Plugin_CMB062022_forumpost.pclr

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That would suggest something wrong with the CAN wiring.  You should have something a little less than 2.5V on CAN low, and a bit above 2.5V on CAN high.  

Are you using a CAN PCB cable?  Possibly pinned wrong in the CANF?

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I am using a CAN PCB cable with the solder-style connector; wired in accordance to this diagram.

Initially, I had CAN Low on pin 2 which resulted in 120 ohms across the two.

I purchased 20awg wire on amazon and twisted it myself; could it be due to an improper twist or spec? The more I looked i came to that conclusion myself, and purchased 50 feet of pre-twisted wire here: https://store.ctr-electronics.com/can-bus-cable/

Thanks for the quick reply!


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Can you pull the CANPCB cable out of the ECU, Leave the complete CAN loom plugged in to the CANPCB.  Unplug the CAN Lambda.  Measure continuity from the green pin at the DTM connector to the green wire in the white JST plug at the ecu end, then do the same with white and also check for continuity between white and green.  

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With no CAN the controller should switch the heater on after 15 seconds to try to protect the sensor.  So it should be at least pretty warm to the touch after 10mins.  So it suggests there is no power.

Can you check power supply by backprobing with pins or similar the Lambda side of the DTM4 connector - like my pic below.  I have for example seen some people assemble the DTM wrong so the terminals push back out and lose contact when you click the plug together.  



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So... I made a silly mistake that I should've noticed quite a while ago. In the same way i goofed up the CAN Low pin in the CANF connector, I had the entire DTM connector pinout mirrored (shown in photos). Once fixed it was immediately detected and started providing data!

Thank you for your time, sorry to have wasted it.

Is there any way to pitch in to the coffee fund? <3


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