Code No.P0568, P0578: Cruise Control Switch System Error










OPERATION




  • When all switches are OFF: 4.7 - 5.0 volts
  • When the "ON/OFF" switch is ON: 0 - 0.5 volt
  • When the "CANCEL" switch is ON: 1.0 - 1.8 volts
  • When the "COAST/SET" switch is ON: 2.3 - 3.0 volts
  • When the "ACC/RES" switch is ON: 3.5 - 4.2 volts

DIAGNOSIS CODE SET CONDITIONS




POSSIBLE CAUSES



  • Damaged harness or connector.
  • Malfunction of the cruise control switch.
  • Malfunction of the clock spring.
  • Malfunction of the engine-ECU.

DIAGNOSIS

STEP 1. Check the data list.
Using M.U.T.-III, check the data list.

  • Item 285: Cruise control switch
(Refer to data list reference table ) <4HN>.

Q. Is the check result normal?
Go to Step 12.
Go to Step 2.

STEP 2. Measure the voltage at cruise control switch connector C-201.
(1)Remove the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ].
(2)Remove the cruise control switch from the steering wheel with the cruise control switch connector connected (Refer to ).
(3)Connect the negative battery terminal that was disconnected when the driver’s air bag module was removed.
(4)Turn the ignition switch to the "ON" position, and do not operate the cruise control switch (all the switches of the cruise control switch are OFF).
(5)Measure the voltage between cruise control switch connector C-201 terminal No. 3 and earth with cruise control switch connector C-201 connected.
OK: 4.7 - 5.0 V
(6)Turn the ignition switch to the "LOCK" (OFF) position.
(7)Install the cruise control switch to the steering wheel (Refer to ).

Q. Is the check result normal?
Go to Step 6.
Go to Step 3.

STEP 3. Connectors check: B-18 engine-ECU connector, C-201 cruise control switch connector, C-202 and C-204 clock spring connectors.

Q. Is the check result normal?
Go to Step 4.
Repair or replace the damaged connectors. Install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 13.

STEP 4. Check the clock spring.
Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring Inspection .

Q. Is the check result normal?
Go to Step 5.
Replace the clock spring and install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 13.

STEP 5. Check the harness between engine-ECU connector B-18 terminal No. 17 and the cruise control switch connector C-201 terminal No. 3.

Q. Is the check result normal?
Install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 11.
Repair the damaged harness wire. Install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 13.

STEP 6. Measure the voltage at cruise control switch connector C-201.
(1)Remove the cruise control switch from the steering wheel with the cruise control switch connector connected (Refer to ).
(2)Turn the ignition switch to the "ON" position.
(3)Press the "ON/OFF" switch with cruise control switch connector C-201 connected, and measure the voltage between terminal No. 2 and earth.
OK: 0.3 V or less
(4)Turn the ignition switch to the "LOCK" (OFF) position.
(5)Install the cruise control switch to the steering wheel (Refer to ).

Q. Is the check result normal?
Go to Step 11.
Go to Step 7.

STEP 7. Connectors check: B-18 engine-ECU connector, C-201 cruise control switch connector, C-202 and C-204 clock spring connectors.

Q. Is the check result normal?
Go to Step 8.
Repair or replace the damaged connectors. Install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 13.

STEP 8. Check the clock spring.
Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring Inspection .

Q. Is the check result normal?
Go to Step 9.
Replace the clock spring and install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 13.

STEP 9. Check the cruise control switch.
Refer to .

Q. Is the check result normal?
Go to Step 10.
Replace the cruise control switch (Refer to ). Install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 13.

STEP 10. Check the harness between engine-ECU connector B-18 terminal No. 5 and the cruise control switch connector C-201 terminal No. 2.

Q. Is the check result normal?
Install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 11.
Repair the damaged harness wire. Install the driver’s air bag module [Refer to GROUP 52B - Driver’s, Front Passenger’s Air Bag Module(s) and Clock Spring ]. Then go to Step 13.

STEP 11. Check the data list.
Using M.U.T.-III, check the data list.

  • Item 285: Cruise control switch
(Refer to data list reference table ) <4HN>.

Q. Is the check result normal?
Go to Step 12.
Replace the engine-ECU (Refer to GROUP 13E - Engine-ECU ). Then go to Step 13.

STEP 12. Read the diagnosis code.
Using M.U.T.-III, read the diagnosis code of the cruise control system (Refer to ).

Q. Is diagnosis code No. P0568 or P0578 set?
Replace the engine-ECU (Refer to GROUP 13E - Engine-ECU ). Then go to Step 13.
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 13. Check the data list.
Using M.U.T.-III, check the data list.

  • Item 285: Cruise control switch
(Refer to data list reference table ) <4HN>.

Q. Is the check result normal?
Go to Step 14.
Return to Step 2.

STEP 14. Read the diagnosis code.
Using M.U.T.-III, read the diagnosis code of the cruise control system (Refer to ).

Q. Is diagnosis code No. P0568 or P0578 set?
Return to Step 1.
The procedure is complete.