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DTC P1A51: EEPROM Fail
 
 
cautionWhenever ECU is replaced, ensure that the CAN bus lines are normal.
 
 
TROUBLE JUDGMENT
Check Condition
  • The power supply mode of the electric motor switch is ON, or the main drive lithium-ion battery starts to be charged.
Judgment Criterion
  • The EEPROM cannot be read or written.
 
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Not available
 
 
PROBABLE CAUSES
  • The battery management unit (BMU) is failed.
  • Disconnect the 12V starter battery during the battery management unit (BMU) activation.
 
 
 
 
DIAGNOSIS
Required Special Tools
  • MB991658: Test harness
STEP 1. Using scan tool (M.U.T.-III), check data list.
Set scan tool (M.U.T.-III) to the data list for item 393 Sum total time back up (Refer to ).
OK: Except 0 month (power supply mode of electric motor switch is ON)
noteWhen power supply mode of electric motor switch is OFF, the battery management unit (BMU) should execute the finishing process for several seconds. When the battery cable is disconnected from the 12V starter battery (-) terminal during the battery management unit (BMU) finishing process, the battery management unit (BMU) learning value could be deleted.
Is the check result normal?
Go to Step 2.
Perform the battery management unit (BMU) learning value manual written (Refer to GROUP 00 - Precautions before Service - Procedures for Writing battery management unit (BMU) Learning Value ). After the battery management unit (BMU) learning value manual written and the main drive lithium-ion battery capacity check (Refer to , go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), check whether the DTC is set again.
Recheck the DTC.
(1) Erase the DTC.
(2) Keep the status with the power supply mode of electric motor switch is OFF for more than 1 minute.
(3) Check the DTC.
Is the DTC set?
Replace the battery management unit (BMU) (Refer to ).
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).