Code No.P0578: Abnormal Voltage at Cruise Control Switches




OPERATION


This circuit judges the signals of each switches (speed limiter ON/OFF, cruise control ON/OFF, CANCEL, SET - and RES +) of the cruise control switches. The PHEV-ECU detects the state of the cruise control switch by sensing the voltages shown below.


DIAGNOSIS CODE SET CONDITIONS




PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. Check the data list.


Using M.U.T.-III, check the PHEV-ECU data list (Refer to GROUP 54D - data list reference table ).

  • Item No.391: Speed limiter on/off switch
  • Item No.392: CANCEL switch
  • Item No.393: RES + switch
  • Item No.394: SET - switch
  • Item No.395: Cruise control on/off switch

Q. Is the check result normal?

Go to Step 19
Go to Step 2

STEP 2. Measure the terminal voltage at cruise control switch connector.


(1)Remove the cruise control switch from the steering wheel with the cruise control switch connector connected (Refer to ).
(2)Connect the negative battery terminal that was disconnected when the driver’s air bag module was removed.
(3)Turn ON the power supply mode of the electric motor switch.
(4)Do not operate the cruise control switch.
(5)Measure the terminal voltage between cruise control switch connector terminal PHEV-ECU CRCS line and earth with cruise control switch connector connected.
OK: 4.7 - 5.0 V

Q. Is the check result normal?

Go to Step 11
Go to Step 3

STEP 3. Measure the terminal voltage at PHEV-ECU connector.


(1)Turn ON the power supply mode of the electric motor switch.
(2)Do not operate the cruise control switch.
(3)Measure the voltage in the CRCS wire between the PHEV-ECU connector and body earth by backprobing.
OK: 4.7 - 5.0 V

Q. Is the check result normal?

Go to Step 8
Go to Step 4

STEP 4. Check the harness wire for short circuit to earth between PHEV-ECU connector terminal CRCS and cruise control switch connector.


(1)Check the PHEV-ECU connector.
(2)Disconnect PHEV-ECU connector and measure at the harness connector side.
(3)Turn OFF the power supply mode of the electric motor switch.
(4)Measure the continuity between PHEV-ECU connector terminal CRCS and earth.
OK: open circuit

Q. Is the check result normal?

Go to Step 18
Go to Step 5

STEP 5. Check the harness wire between PHEV-ECU connector terminal CRCS and clock spring connector, and between clock spring connector terminal and cruise control switch connector.



  • Check connector or harness wire for short circuit and damage.

Q. Is the check result normal?

Go to Step 6
Repair connector or damaged harness wire. Then go to Step 20.

STEP 6. Check the clock spring.


Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .

Q. Is the check result normal?

Go to Step 7
Replace the clock spring, and install the driver’s air bag module (Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring ). Then go to Step 20.

STEP 7. Check the cruise control switches.


Refer to .

Q. Is the check result normal?

Go to Step 10
Replace the cruise control switches (Refer to ). Then go to Step 20.

STEP 8. Check the harness wire between PHEV-ECU connector terminal CRCS and clock spring connector, and between clock spring connector and cruise control switch connector.



  • Check connector or harness wire for open circuit and damage.

Q. Is the check result normal?

Go to Step 9
Repair connector or damaged harness wire. Then go to Step 20.

STEP 9. Check the clock spring.


Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .

Q. Is the check result normal?

Go to Step 10
Replace the clock spring, and install the driver’s air bag module (Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring ). Then go to Step 20.

STEP 10. Check the data list.


Using M.U.T.-III, check the PHEV-ECU data list (Refer to GROUP 54D - data list reference table ).

  • Item No.391: Speed limiter on/off switch
  • Item No.392: CANCEL switch
  • Item No.393: RES + switch
  • Item No.394: SET - switch
  • Item No.395: Cruise control on/off switch

Q. Is the check result normal?

Go to Step 19
Go to Step 11

STEP 11. Measure the terminal voltage at cruise control switch connector.


(1)Remove the cruise control switch from the steering wheel with the cruise control switch connector connected (Refer to ).
(2)Turn ON the power supply mode of the electric motor switch.
(3)Press the cruise control ON/OFF switch with cruise control switch connector connected, and measure the terminal voltage between cruise control switch connector terminal PHEV-ECU CRCG line and earth.
OK: 0.9 - 1.7 V

Q. Is the check result normal?

Go to Step 15
Go to Step 12

STEP 12. Measure the terminal voltage at PHEV-ECU connector.


(1)Turn ON the power supply mode of the electric motor switch.
(2)Press the cruise control ON/OFF switch, and then measure the voltage in the CRCG wire between the PHEV-ECU connector and body earth by backprobing.
OK: 0.9 - 1.7 V

Q. Is the check result normal?

Go to Step 13
Go to Step 18

STEP 13. Check the harness wire between PHEV-ECU connector terminal CRCG and clock spring connector, and between clock spring connector and cruise control switch connector.



  • Check connector or harness wire for open circuit and damage.

Q. Is the check result normal?

Go to Step 14
Repair connector or damaged harness wire. Then go to Step 20.

STEP 14. Check the clock spring.


Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .

Q. Is the check result normal?

Go to Step 18
Replace the clock spring, and install the driver’s air bag module (Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring ). Then go to Step 20.

STEP 15. Check the harness wire between PHEV-ECU connector terminal CRCG and clock spring connector, and between clock spring connector and cruise control switch connector.



  • Check connector or harness wire for short circuit and damage.

Q. Is the check result normal?

Go to Step 16
Repair connector or damaged harness wire. Then go to Step 20.

STEP 16. Check the clock spring.


Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .

Q. Is the check result normal?

Go to Step 17
Replace the cruise control switches (Refer to ). Then go to Step 20.

STEP 17. Check the cruise control switches.


Refer to .

Q. Is the check result normal?

Go to Step 18
Replace the cruise control switches (Refer to ). Then go to Step 20.

STEP 18. Check the data list.


Using M.U.T.-III, check the PHEV-ECU data list (Refer to GROUP 54D - data list reference table ).

  • Item No.391: Speed limiter on/off switch
  • Item No.392: CANCEL switch
  • Item No.393: RES + switch
  • Item No.394: SET - switch
  • Item No.395: Cruise control on/off switch

Q. Is the check result normal?

Go to Step 19
Replace the PHEV-ECU (Refer to GROUP 54D - PHEV-ECU ). Then go to Step 20.

STEP 19. Read the diagnosis code.


(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system.
(2)Turn ON the power supply mode of the electric motor switch, and press the cruise control ON/OFF switch to turn the cruise control system to ON (the cruise control display screen is turned on).
(3)After turning the cruise control system to ON, when 2 minutes or more has elapsed without operating the cruise control switches, read the diagnosis code of the cruise control system (Refer to ).

Q. Is diagnosis code No. P0578 stored?

Replace the PHEV-ECU (Refer to GROUP 54D - PHEV-ECU ). Then go to Step 20.
It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunction ).

STEP 20. Check the data list.


Using M.U.T.-III, check the PHEV-ECU data list (Refer to GROUP 54D - data list reference table ).

  • Item No.391: Speed limiter on/off switch
  • Item No.392: CANCEL switch
  • Item No.393: RES + switch
  • Item No.394: SET - switch
  • Item No.395: Cruise control on/off switch

Q. Is the check result normal?

Go to Step 21
Return to Step 2.

STEP 21. Read the diagnosis code.


(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system.
(2)Turn ON the power supply mode of the electric motor switch, and press the cruise control ON/OFF switch to turn the cruise control system to ON (the cruise control display screen is turned on).
(3)After turning the cruise control system to ON, when 2 minutes or more has elapsed without operating the cruise control switches, read the diagnosis code of the cruise control system (Refer to ).

Q. Is diagnosis code No. P0578 stored?

Return to Step 1.
The procedure is complete.