Engine Harness - Part 5 - Debugging CAN wires
TLDR
- Traced and fixed the CAN wires.
Details
Tracing CAN wires
Continuing the work from last week, I focused on the CAN wiring between the ECU and the G3X. Three sets of connectors are involved: HIC-A & HIC-B, the J244 connector on the GEA24, and a jumper connector in between.
The most probable issue was with the jumper connector, so I cut several zip-ties to reach it and disconnected it from the harness.
With the connector on the bench, it became clear that the wires were not jumped at all; it was just a pigtail. I suspect MWPB left the connector as a pigtail to provide the option to either use it as a jumper or connect it to an SCU. Since I don’t have an SCU, I needed to jump the wires myself.
I used a multimeter to test the continuity of the wires between the jumper connector and the J244 pins, as well as between the jumper and the HIC-A/B pins, to understand how the wires were internally connected.
Here is what I found:
Based on the diagram, it was clear that I needed to connect the six jumper wires into two groups:
- Pin 5+7+4
- Pin 6+8+3
I used crimp splices to connect the wires in the correct configuration.
I then wrapped the connections in silicone tape for protection.
Afterward, I put everything back together in reverse order and turned the power back on.
Success! The engine instruments are now showing the correct values.