Code No. U1901: K-line slave lost among BMUs
Code No. U1911: K-line between BMUs reception error


caution If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, always diagnose the CAN bus lines.
MAIN BATTERY MANAGEMENT SYSTEM CIRCUIT



OPERATION



  • The CAN communication between BMUs and EV-ECU is backed up by the K-LINE communication.

DIAGNOSIS CODE SET CONDITIONS



  • If the K-LINE (back-up) communication data from the BMU cannot be received, the diagnosis code No. U1901 will be set.
  • If the K-LINE (back-up) communication data from the BMU is parity error or checksum, the diagnosis code No. U1911 will be set.

PROBABLE CAUSES



  • Damaged wiring harness or connector(s)
  • Malfunction of the BMU system

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III CAN bus diagnosis
Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 3.
Repair the CAN bus line. (Refer to GROUP 54C - Troubleshooting .) Then go to Step 2.

STEP 2. Check whether the diagnosis code is reset.
Check again if the diagnosis code No. U1901 or No. U1911 is set to the EV-ECU.
(1)Erase the stored diagnosis code.
(2)Set the electric motor switch from the "LOCK" (OFF) position to the "ON" position.
(3)Check if the diagnosis code is set.

Q. Is the diagnosis code set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Connector check: C-107 BMU connector, C-106 EV-ECU connector

Q. Is the check result normal?
Go to Step 4.
Repair the damaged connector.

STEP 4. Check the wiring harness between C-107 BMU connector terminal No. 8 and C-106 EV-ECU connector terminal No. 16.
Check the signal lines for open circuit.

Q. Is the check result normal?
Go to Step 5.
Repair the wiring harness.

STEP 5. Use M.U.T.-III to confirm a diagnosis code of other systems.
Check if the diagnosis code is set to BMU.

Q. Is the diagnosis code set?
Carry out troubleshooting for the BMU. (Refer to Diagnosis Code Chart .) Then go to Step 6.
Go to Step 6.

STEP 6. Diagnosis code recheck
Check again if the diagnosis code is set to the EV-ECU.
(1)Erase the stored diagnosis code.
(2)Set the electric motor switch from the "LOCK" (OFF) position to the "ON" position.
(3)Check if the diagnosis code is set.

Q. Is the diagnosis code set?
Return to Step 1.
The diagnosis is complete.