Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2014 2015 2016)
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
- 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.
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 |
| 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 ECU |
| Power seat control unit | Memory Seat Control Unit |
| Parking and back-up control unit | Parking Sensor Module |
| Telematics control unit | Telematics (OnStar) Control Unit |
| HandsFreeLink control unit | Hands Free Link Unit |
| Front seat heater control unit | Seat Heater Control Unit |
| Second row seat heater control unit | 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 the vehicle is not equipped, "NOT AVAILABLE" is displayed.
- The HDS only checks the status one time when BODY ELECTRICAL is selected. To recheck the status after repair, reboot 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 (2014 2015 2016) .
- If all units are not communicating or only the MICU is communicating, go to MICU DTC U1280 troubleshooting - Refer to: DTC U1280 (2014 2015 2016) .
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:
- Battery voltage DTCs.
- Internal error DTCs.
- Loss of communication DTCs.
- Signal error DTCs.