MSB is released for this page as follows:

Release Date	Subject	MSB No.
2011-11-20	ELECTRIC MOTOR UNIT AND MAIN BATTERY TROUBLESHOOTING	MSB-11E54-515
2018-12-20	Correction of the diagnosis procedure of TROUBLESHOOTING about Electric Motor and Main Drive Lithium-Ion Battery	MSB-11E54-515A

Code No. P1A51: EEPROM Abnormal (BMU)

TROUBLE JUDGMENT

Check Conditions

The electric motor switch is "ON" position or while the main battery is charged.
After the BMU is activated, failures are not detected even once.

Judgement Criterion

The EEPROM cannot be read or written.

FAIL-SAFE AND BACKUP FUNCTION

Not available

PROBABLE CAUSES

The BMU is failed.
Disconnect the auxiliary battery during the BMU activation.

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Erase the diagnosis code.
Item 277: Overall time backup

OK: Except 2 month (electric motor switch: ON)

note

When the electric motor switch is turned in the LOCK (OFF) position, the BMU should execute the finishing process for several seconds. When the battery cable is disconnected from the auxiliary battery (-) terminal during the BMU finishing process, the BMU learning value could be deleted.

Q. Is the check result normal?

	Go to Step 2 .

	Perform the BMU learning value manual written (Refer to GROUP 00 - Precautions before Service - Procedures for Writing BMU Learning Value ). After the BMU learning value manual written, go to Step 2 .

STEP 2. M.U.T.-III diagnosis code.

Before checking the diagnosis code again, keep the status with the electric motor switch in the LOCK (OFF) position for more than 1 minute.

Q. Is the diagnosis code set?

	Replace the BMU.

	Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

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