Code No. P0A90: Motor overcurrent continuation abnormality (MCU)


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.
ELECTRIC MOTOR UNIT CONTROL SYSTEM CIRCUIT



DIAGNOSIS CODE SET CONDITIONS



PROBABLE CAUSES



  • Damaged high-voltage harness wires
  • Malfunction of the motor (electric motor unit)
  • 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 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. ?Check whether the diagnosis code is set.
Check if the diagnosis code No. P1A29 for other systems is set to the MCU.

Q. Is the diagnosis code set?
Carry out troubleshooting for the diagnosis code No. P1A29. (Refer to .) Then go to Step 4.
Go to Step 4.

STEP 4. High-voltage connector check: G-07, G-08, G-09 MCU high-voltage terminal
danger Carry out the check on the high-voltage circuit while reading carefully the precautions on handling a high-voltage vehicle. (Refer to .)
danger Wear the specified protection equipment during the check.
(1)Shut down the high voltage.
(2)Check that the following terminals are tightened to the specified torque. (Refer to .)

  • G-07, G-08, G-09 MCU high-voltage terminal

Q. Is the check result normal?
Go to Step 5.
Tighten the high-voltage terminal to the specified torque. (Refer to .)

STEP 5. 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 the diagnosis code set?
Replace the MCU.(Refer to .) Then go to Step 6.
The diagnosis is complete.

STEP 6. 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 the diagnosis code set?
Replace the motor (electric motor unit). (Refer to .) Then go to Step 7.
The diagnosis is complete.

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 the diagnosis code set?
Go to Step 1.
The diagnosis is complete.