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.
DIAGNOSIS CODE SET CONDITIONS
If the torque command absolute value from the EV-ECU is kept at 181 Nm or more when the EV-ECU control mode is the driving mode, the MCU will set the diagnosis code No. P1A27.
PROBABLE CAUSES
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. Check whether the diagnosis code is reset.
Check again if the diagnosis code No. P1A27 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)Set the electric motor switch to the LOCK (OFF) position, and start the electric motor unit.
(4)Check if the diagnosis code is set.
Q.
Is the diagnosis code set?
Go to Step 3.
This diagnosis is complete.
STEP 3. Use M.U.T.-III to confirm a diagnosis code of other systems.
Check if the diagnosis code is set to the EV-ECU.
Q.
Is the diagnosis code set?
Carry out troubleshooting for the EV-ECU. (Refer to .) Then go to Step 4.
Go to Step 4.
STEP 4. 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)Set the electric motor switch to the LOCK (OFF) position, and start the electric motor unit.
(4)Check if the diagnosis code is set.
Q.
Is the diagnosis code set?
Replace the MCU. (Refer to .) Then go to Step 5.
The diagnosis is complete.
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)Set the electric motor switch to the LOCK (OFF) position, and start the electric motor unit.
Go to Step 3.
Repair the CAN bus line. (Refer to GROUP 54C - Troubleshooting 
.) Then go to Step 2.