VMI3 Basic Usage: CAN-FD Waveform Measurement

Step 1: Preparation and Equipment Connection

• Test vehicle: KONA (SX2) G1.6 T-GDI
• Connect the GDS Smart VMI3 diagnostic module to the vehicle's engine compartment.
• On the diagnostic tablet, launch 'Tool Box' > Oscilloscope mode from the GDS Smart main screen.

Step 2: Probe Connection Guide

The oscilloscope probe must be connected accurately to the P-CAN (Powertrain CAN) line. Measurement should be performed with [IG ON] or [engine idling].

• Channel A (CH.A) - Measuring CAN High line
  • (+) Probe: Connect to P-CAN High line (Pin 45)
  • (-) Probe: Connect to battery (-) terminal (vehicle chassis ground)
• Channel B (CH.B) - Measuring CAN Low line
  • (+) Probe: Connect to P-CAN Low line (Pin 33)
  • (-) Probe: Connect to battery (-) terminal (vehicle chassis ground)

Step 3: Oscilloscope Environment Settings

To clearly capture the high-speed CAN-FD communication signal, set up the environment as follows.

• Voltage Range (Volt/Division): Set to 4V
• Time Range (Time/Division): Set to 100μS
• To analyze the waveform stably, use the on-screen Auto-CH, Single-shot, Trigger, Zero Set buttons, etc., to pause and adjust the waveform.

Step 4: Waveform Analysis and Normal Criteria

If the equipment and probes are connected properly, two channel waveforms will be displayed on the screen.

• Green waveform (CH-A / CAN High): Oscillates rising between reference voltage 2.5V and 3.5V
• Yellow waveform (CH-B / CAN Low): Oscillates falling between reference voltage 2.5V and 1.5V