Signal Circuit Inspection

■ Check CAN high communication circuit 

1. Ignition "ON" and Engine "OFF".
2. Connect scantool and select VEHICLE SCOPEMETER function.
3. Measure waveform between terminal "8" of DDM ECU and chassis ground.

   Specification  : CAN communication waveform is displayed

   Fig 1: Measuring Waveform Between Terminal 8 Of DDM ECU And Chassis Ground

   Courtesy of HYUNDAI MOTOR CO.
4. Is the measured waveform within specifications?

   ■ The existence of CAN communication waveform itself shows there's no trouble in CAN communication circuit. If there's any short in harness, no signal is detected.

   YES 

   • Go to  1 Check CAN low communication circuit procedure.

   NO 

   • Check for short circuit in signal harness. Repair as necessary and go to "VERIFICATION VEHICLE REPAIR " procedure.

   ■ Check CAN low communication circuit 

   1. Ignition "ON" and Engine "OFF".
   2. Connect scantool and select VEHICLE SCOPEMETER function.
   3. Measure waveform between terminal "9" of DDM ECU and chassis ground.

      Specification  : CAN communication waveform is displayed

      Fig 2: Measuring Waveform Between Terminal 9 Of DDM ECU And Chassis Ground

      Courtesy of HYUNDAI MOTOR CO.
   4. Is the measured waveform within specifications?

      ■ The existence of CAN communication waveform itself shows there's no trouble in CAN communication circuit. If there's any short in harness, no signal is detected

      YES 

      • Go to "COMPONENT INSPECTION " procedure.

      NO 

      • Check for short circuit in signal harness. Repair as necessary and go to "VERIFICATION VEHICLE REPAIR " procedure.