H-CAN Communication Inspection

■ Check Resistance of H-CAN Communication Line 

1. IG KEY OFF.
2. Disconnect Aux. battery (-) cable.
3. Wait for 5 minutes after turning main switch OFF.
4. Disconnect BMS ECU connector.
5. Check resistance between H-CAN LOW signal and H-CAN HIGH signal terminal of disconnected BMS ECU connector.

   Specification:  Specification: Approx. 120 Ω

   WARNING: * Warning & Notice
   Hybrid Battery system uses around 270V voltage.
   It may cause death or damage due to electrical shock, if you Do Not follow below Instructions.

   • Follows instructions of workshop handbook.
   • Wear and use insulated gloves and tools.
   • IG "OFF", Disconnect ground cable of auxiliary battery and "OFF" the safety connector of the high voltage battery.
   • Check high voltage terminal on Power Relay Assembly is lower than 30V.
   • Be careful that it should not be short between terminals when measuring battery cell voltage. You may be injured due to spark, parts damage or electrical shock.
   • Metallic material cause high voltage short that may cause damage of life or vehicle. Therefore, get rid of all the metallic material before working. (Metallic Material: Watch, Ring, any metallic products etc.).
   • After disconnect W/H goes to BMS ECU from High voltage battery, be careful not to happen short between exposed terminal and terminal on high voltage connector.
   Fig 1: Checking Resistance Between H-CAN Low Signal And H-CAN High Signal Terminal Of BMS ECU Connector

   Courtesy of HYUNDAI MOTOR AMERICA
   Fig 2: PCM Connector End View

   Courtesy of HYUNDAI MOTOR AMERICA
6. Is the measured value within specification?

   YES 

   • Perform checking signal waveform of "H-CAN Low and H-CAN HIGH.

   NO 

   • The resistance value is around 1.0 Ω: Repair as necessary after finding short between H-CAN HIGH and H-CAN LOW. And then, go to "VERIFICATION OF VEHICLE REPAIR " Procedure.
   • In case of infinity Ω: Repair open or short circuit of H-CAN. Go to "VERIFICATION OF VEHICLE REPAIR " procedure.

■ Check Signal Waveform of H-CAN LOW Signal Circuit and H-CAN HIGH Signal 

1. IG KEY OFF.
2. Connect BMS ECU connector.
3. Maintain EV mode at Idle or Acceleration after starting.
4. Measure signal waveform of H-CAN LOW signal and H-CAN High signal of MCU connector.

   Specification:  Signal waveform is as same as standard signal waveform

   Fig 3: Measuring Signal Waveform Of H-CAN LOW Signal And H-CAN High Signal Of MCU Connector

   Courtesy of HYUNDAI MOTOR AMERICA
   Fig 4: PCM Connector End View

   Courtesy of HYUNDAI MOTOR AMERICA
5. Is the measured value within specification?

   YES 

   • Go to "COMPONENT INSPECTION " procedure.

   NO 

   • Check battery, ground or short each other in H-CAN LOW and H-CAN High of MCU Repair as necessary. Go to "VERIFICATION OF VEHICLE REPAIR " procedure.