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DTC P1028: Front motor shutdown circuit(1)
cautionBefore replacing the ECU, ensure that the communication circuit is normal.
 
 
 
 
MONITOR EXECUTION
Continuous
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
  • EV-CAN monitor
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart
 
 
Check Conditions
  • The PHEV-ECU power supply voltage is more than 9.0 volts.
  • The start signal of the motor/generator control circuit is OFF
Judgment Criterion
  • When a state with the motor/generator control circuit ON continues for 1 second when the start signal of the motor/generator control circuit is OFF
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
 
 
PROBABLE CAUSES
  • The 12 volts starter battery is flat.
  • Malfunction of the 12 volts starter battery.
  • Loose 12 volts starter battery terminal.
  • Damaged harness or connector.
  • Malfunction of the power drive unit.
  • Malfunction of the PHEV-ECU.
 
 
 
DIAGNOSIS
Required Special Tools
  • MB991223: Wiring harness set
  • MB992006: Extra fine probe
STEP 1. Check the voltage at the power drive unit connector (terminal MSDN).
Disconnect the FEMCU connector with the power supply mode of the electric motor switch turned on (not READY), and then check the voltage.
OK: Approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 3.
go to Step 2.
 
STEP 2. Check the signal line for short circuit (PHEV-ECU connector and power drive unit connector).
Check the wiring harness between PHEV-ECU connector (terminal MSDN) and the power drive unit connector (terminal MSDN).
Is the check result normal?
Go to Step 3.
Repair the connector or wiring harness. Then go to Step 6.
 
STEP 3. Using scan tool (M.U.T.-IIISE), check the data list <FEMCU>.
Check that the following data list display contents are normal. (Refer to GROUP 54Db - Service Data Reference Table, Data List ).
Data list
  • Item No.5: MCU shutdown request
 
Check conditionNormal condition
The PHEV-ECU does not request the MCU to shut down the high voltage with the power supply mode of the electric motor switch turned on.No
The PHEV-ECU requests the MCU to shut down the high voltage with the power supply mode of the electric motor switch turned on.Yes
Is the check result normal?
Go to Step 4.
Replace the power drive unit (Refer to GROUP 54Db - Power Drive Unit Removal and Installation ). Then go to Step 6.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check the data list <FEMCU>.
Check that the following data list display contents are normal. (Refer to GROUP 54Db - Service Data Reference Table, Data List ).
Data list
  • Item No.25: HW shutdown
 
Check conditionNormal condition
The PHEV-ECU does not request the MCU to shut down the high voltage with the power supply mode of the electric motor switch turned on.ON
The PHEV-ECU requests the MCU to shut down the high voltage with the power supply mode of the electric motor switch turned on.OFF
Is the check result normal?
Go to Step 5.
Replace the power drive unit (Refer to GROUP 54Db - Power Drive Unit Removal and Installation ). Then go to Step 6.
 
STEP 5. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
(2) Check the DTC.
Is the DTC set?
Replace the PHEV-ECU (Refer to ). Then go to Step 6.
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
 
STEP 6. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
(2) Check the DTC.
Is the DTC set?
Retry the troubleshooting.
The procedure is complete.