Trailer Guide Schematics Software

PC interface to DIAGN/CAN

Find here extended description, connector views, and help for diagnostic as well !

Description

  • To connect PC Interface to ECU DIAGN socket.
  • Cable insulation material : PVC

SUB-D 25 pin plug

DB25 plug.png

Pin Description Color Section (mm2)
25 B+ Red 0.75
22 B- Blue 0.75
16 CAN High Green 0.75
15 CAN Low Yellow 0.75

 

Diagnostic

ISO11898 - SUB-D 25 only !

The Haldex Can Bus uses 4 wires, 2 are for power supply, 2 for the communication (CAN High and CAN Low)

It can be used for ECU extensions, diagnostic or telematic.

 

Before to check on one of the wire, be sure you know the CANbus layout of the vehicle. Depending on the ECUs mounted, you could find splitters and extension cables to link all the network together.

In practice, always start to check the CANbus from one end to main ECU (EB+ or U-ABS), then check again the different cable or splitters separately.

Test points Condition Required value Mesured value Comments
25 / 22 Power ON  B+  

If the mesured value is below B+, it can indicate a resistance in the wiring

Next steps :

  • check for oxidation marks in the connectors
  • check the continuity of the wires with ohmmeter (R<5Ω for correct operation)
16 / 22 Power ON

0V < V < 5V

  

The average voltage of CAN High wire is around 2.5V

Next steps :

  • check for oxidation marks in the connectors
  • check the continuity of the wires with ohmmeter (R<5Ω for correct operation)
15 / 22 Power ON  0V < V < 5V  

The average voltage of CAN Low wire is around 2.5V

Next steps :

  • check for oxidation marks in the connectors
  • check the continuity of the wires with ohmmeter (R<5Ω for correct operation)

DIAGN/CAN plug

Can Plug ok.png

Pin Description Color Section (mm2)
1 B+ Red 0.75
2 CAN High Green 0.75
3 CAN Low Yellow 0.75
4 B- Blue 0.75

 "A" indicate the clip side

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