Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2017 2018 2019 2020)

Check the PCM for DTCs and troubleshoot PCM or F-CAN loss of communication errors first, then do this diagnosis if the symptom is related to the B-CAN system.

1. Compare the symptom with this list of B-CAN related systems:

• Audio, navigation, and telematics control
• Headlight leveling control
• Auto-high beam
• Multi view camera system
• Parking and back-up control
• Gauge control module
• Exterior lights
• Turn signals
• Entry light control
• Interior lights
• Safety indicators
• Horns (security and panic)
• Reminder chimes (key-in, seat belt, lights-on, and parking brake)
• Power window/moonroof timer
• Wiper/washer
• Security
• Keyless entry
• Key interlock
• Power door locks
• Dashlights brightness
• Immobilizer
• Daytime running lights
• Driving position memory system
• Keyless access control
• Climate control
• Power tailgate
• BSI system
• Seat heater

• If the symptom is related to the B-CAN, go to step 2.
• If the symptom is not related to the B-CAN, go to the system symptom troubleshooting.

2. Connect the HDS to the data link connector (DLC) (A), then turn the vehicle to the ON mode.

Courtesy of HONDA, U.S.A., INC.

3. From the BODY ELECTRICAL SYSTEM SELECT menu, and then select B-CAN CONTROL UNITS INFORMATION listed to see if the following control units are communicating with the HDS.

Control units	HDS name
MICU	MICU
Gauge control module	Gauge Control Module (Diag-CAN)
Relay control module	Relay Unit
Door multiplex control unit	Power Window Unit
Climate control unit	Climate Control Unit / HVAC Control Unit
Automatic lighting/rain sensor	Rain Light Sensor Unit
Keyless access/TPMS control unit	Keyless Access Unit
Power seat control unit	Power Seat Control Unit
Parking and back-up control unit	Parking Sensor Module
Telematics control unit	Telematics Control Unit
HandsFreeLink control unit	Hands Free Link Unit
Front seat heater control unit / Ventilated seat control unit	Seat Heater Control Unit
Second row seat heater control unit	Rear Seat Heater Control Unit
Power tailgate control unit	Power Tailgate Unit
Rear MICU	Rear Junction Unit
Multi view camera unit	Multi View Camera System

NOTE: 

• If a unit is communicating with the HDS, "DETECT" is displayed.
• If a unit is not communicating or not equipped, "Not Available" is displayed.
• The HDS checks the status only one time when BODY ELECTRICAL is selected. To recheck the status after a repair, restart the HDS.

• If all control units are communicating with the HDS, go to step 4.
• If any of the control units are not communicating, go to B-CAN System Diagnosis Test Mode B - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not Communicating (2017 2018 2019 2020),  or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not Communicating (2014 2015 2016) 
• If all units are not communicating or only the MICU is communicating, go to MICU DTC U1280 troubleshooting - Refer to: DTC Troubleshooting: U1280 (MICU (Multiplex Integrated Control Unit)) (2014 2015 2016), or DTC Troubleshooting: U1280 (2017 2018 2019 2020) .

4. Select the system that has the problem from the BODY ELECTRICAL SYSTEM SELECT menu, then select DTCs.

• If any DTCs are indicated, go to step 5.
• If the problem is related to one of the following items and the system that is malfunctioning does not stop or turn off, go to B-CAN System Diagnosis Test Mode C - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode C - No DTCs and Output Won't Shut OFF, 
• If the problem is related to one of the following items and the system that is malfunctioning does not run or turn on, go to B-CAN System Diagnosis Test Mode D - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode D - No DTCs and Output Won't Turn ON, 
• • Exterior lights
  • Turn signals
  • Entry light control
  • Interior lights
  • Horns (security and panic)
  • Wiper/washer
  • Power window
  • Power door locks
• If the problem is related to one of the following items, go to the troubleshooting for that individual system.
• • Gauge control module
  • Safety indicators
  • Reminder chimes (key-in, seat belt, lights-on, and parking brake)
  • Security
  • Keyless entry
  • Dashlights brightness
  • Immobilizer
  • Rear window defogger (climate control)
  • Climate control
  • Keyless access control
  • Driving position memory system
  • Parking and back-up sensor system
  • Power tailgate
  • Seat heater

5. Record all DTCs, and sort them by DTC type, then troubleshoot them in this order:

• Internal error DTCs.
• Loss of communication DTCs.
• Signal error DTCs.