Code No.P1031: Electrical parking lock system malfunction



caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be stored. Prior to this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
  • Whenever ECU is replaced, ensure that the CAN bus lines are normal.

TROUBLE JUDGEMENT


The PHEV-ECU stores this diagnosis code when the electric parking lock system fails.

PROBABLE CAUSES



  • Malfunction of CAN bus
  • Damaged harness or connector
  • Malfunction of electrical parking relay (stuck OFF)
  • The electric parking actuator fails (any of U, V, W phases stuck on or off)
  • The electric parking driver unit fails (internal error)
  • Malfunction of PHEV-ECU

DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnostics


Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result normal?

Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54C - Troubleshooting ). On completion, go to Step 2.

STEP 2. M.U.T.-III data list (Electrical parking driver unit)


Check that the following data list display contents are normal (Refer to GROUP 22D - Data List Reference Table ).
Data list
  • Item 6: Motor all-phase fail flag
  • Item 7: Motor one-phase fail flag
  • Item 17: ECU fail flag
Check condition
Normal condition
The parking lock status
Normal
OFF
Abnormal
ON

Q. Is the check result normal?

Go to Step 12.
Go to Step 3.

STEP 3. Check electrical parking relay.


Refer to GROUP 22D - Electrical Parking Relay Check .

Q. Is the check result normal?

Go to Step 4.
Replace the electrical parking relay.

STEP 4. Voltage measurement at the electrical parking relay connector.


(1)Remove the electric parking relay, and measure at the relay box side.
(2)Measure the voltage between terminal No.3, 4 and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 6.
Go to Step 5.

STEP 5. Check the power supply line for open and short circuit. (fusible link 8 and selector lever assembly).



  • Check the wiring harness fusible link 8 and electrical parking relay connector terminal No. 4.

Q. Is the check result normal?

Go to Step 6.
Repair the connector or wiring harness.

STEP 6. Voltage measurement at the electrical parking driver unit connector


(1)Install the electric parking relay.
(2)Disconnect the electric parking driver unit connector and measure at the wiring harness side.
(3)Measure the voltage between BMB terminal and body earth
OK: System voltage

Q. Is the check result normal?

Go to Step 8.
Go to Step 7.

STEP 7. Check the power supply line for open and short circuit. (Electrical parking relay and electrical parking driver unit).



  • Check the wiring harness electrical parking relay connector terminal No.1 and electrical parking driver unit (BMB terminal) connector.

Q. Is the check result normal?

Go to Step 8.
Repair the connector or wiring harness.

STEP 8. Check the power supply line for open and short circuit. (Electrical parking actuator and electrical parking relay).



  • Check the wiring harness electrical parking actuator connector terminal No.4 and electrical parking relay connector terminal No. 2.

Q. Is the check result normal?

Go to Step 9.
Repair the connector or wiring harness.

STEP 9. Check the signal line for open and short circuit. (Electrical parking actuator and electrical parking driver unit).



  • Check the wiring harness electrical parking actuator connector terminals No.5, 10, 9 and electrical parking driver unit (MBU, MBV, MBW terminal) connector.

Q. Is the check result normal?

Go to Step 10.
Repair the connector or wiring harness.

STEP 10. Check electrical parking actuator.


Refer to GROUP 22D -Inspection .

Q. Is the check result normal?

Go to Step 11.
Replace the electrical parking actuator (Refer to GROUP 22D- Electrical Parking Actuator ).

STEP 11. Check whether the diagnosis code is stored again.


Recheck if the diagnosis code is stored.
(1)Erase the diagnosis code.
(2)Turn on the power supply mode of the electric motor switch.
(3)Check if the diagnosis code is stored.

Q. Is the diagnosis code stored?

Replace the electrical parking driver unit (Refer to GROUP 22D - Electrical Parking Drive Unit ).
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

STEP 12. Check whether the diagnosis code is stored again.


Recheck if the diagnosis code is stored.
(1)Erase the diagnosis code.
(2)Turn on the power supply mode of the electric motor switch.
(3)Check if the diagnosis code is stored.

Q. Is the diagnosis code stored?

Replace the PHEV-ECU (Refer to ).
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).