Code No. U1920: K-line error (MCU)


ELECTRIC MOTOR UNIT CONTROL SYSTEM CIRCUIT





DIAGNOSIS CODE SET CONDITIONS



PROBABLE CAUSES



  • Malfunction of the K-LINE
  • Malfunction of the EV-ECU
  • Malfunction of the MCU

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. Diagnosis code recheck
Check again if the diagnosis code No. U1920 is set to the MCU.
(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.
The diagnosis is complete.

STEP 3. Connector check: C-110 EV-ECU connector, E-06 MCU connector

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

STEP 4. Check the wiring harness between C-110 EV-ECU connector terminal No. 76 and E-06 MCU connector terminal No. 9.

  • Check the K-LINE for short circuit.

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

STEP 5. Measure the voltage at E-06 MCU connector.
(1)Disconnect the connector and measure at the wiring harness side.
(2)Measure the voltage between the E-06 MCU connector No.9 and the body earth.
OK: 5 V or more

Q. Is the check result normal?
Go to Step 6.
Replace the EV-ECU. (Refer to .) Then go to Step 8.

STEP 6. Voltage measurement at C-110 EV-ECU connector
(1)Disconnect the connector and measure at the wiring harness side.
(2)Measure the voltage between the C-110 EV-ECU connector terminal No. 76 and the body earth.
OK: 5 V or more

Q. Is the check result normal?
Go to Step 7.
Replace the MCU. (Refer to .) Then go to Step 8.

STEP 7. Diagnosis code recheck
Check again if the diagnosis code is set to the MCU.
(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 any diagnosis code set?
Go to Step 1.
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction .)

STEP 8. Diagnosis code recheck
Check again if the diagnosis code is set to the MCU.
(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 any diagnosis code set?
Go to Step 1.
The diagnosis is complete.