Inspection Procedure 1: Steering Wheel Remote Control Switch does not Function. <Vehicles with Radio and CD Changer>


caution Before replacing the ECU, ensure that the power supply circuit, the earth circuit and the communication circuit are normal.








TECHNICAL DESCRIPTION (COMMENT)


The power supply circuit to the steering wheel remote control switch, the steering wheel remote control switch, the radio and CD player or CD changer, or the clock spring may be defective.

PROBABLE CAUSES



DIAGNOSIS

STEP 1. Using M.U.T-III MB991958, check data list.


Check whether the service data below are normal.
(1)Turn the ignition switch to "ON" position.
(2)Operate each switch of the steering wheel remote control. Check whether the normal conditions listed below are displayed.
Item No.
 Item name
 Normal condition
Item 1
 RADIO remoto SW (SEEK-)
 ON
Item 2
 RADIO remoto SW (SEEK+)
 ON
Item 3
 RADIO remoto SW (MODE)
 ON
Item 4
 RADIO remoto SW (VOL-)
 ON
Item 5
 RADIO remoto SW (VOL+)
 ON
OK: Normal condition is displayed.

Q. Is the check result normal?
Replace the radio and CD player or CD changer.
Go to Step 2.

STEP 2. Check the steering wheel remote control switch.
Check the steering wheel remote control switch (Refer to ).

Q. Is the check result normal?
Go to Step 3.
Replace the steering wheel remote control switch.

STEP 3. Connector check: D-302 and D-305 clock spring connector

Q. Are clock spring connector D-302 and D-305 in good condition?
Go to Step 4.
Repair the defective connector.

STEP 4. Check the clock spring.
Check whether the clock spring is in good condition (Refer to GROUP 52B - Air bag module and clock spring ).

Q. Is the check result normal?
Go to Step 5.
Replace the clock spring.

STEP 5. Connector check: D-209 radio and CD player or CD changer connector

Q. Is the check result normal?
Go to Step 6.
Repair the defective connector.

STEP 6. Check the wiring harness between D-209 radio and CD player or CD changer connector terminal No.22, 32 and D-305 clock spring connector terminal No.2, 3.

  • Check the communication lines for open or short circuit.

Q. Is the check result normal?
Go to Step 7.
Repair the wiring harness.

STEP 7. Connector check: D-312 steering wheel remote control switch connector

Q. Is the check result normal?
Go to Step 8.
Repair or replace the damaged component(s). The steering wheel remote control switch should work normally.

STEP 8. Check the wiring harness between D-312 steering wheel remote control switch connector terminal No.1, 3 and D-302 clock spring connector terminal No.4, 5.

  • Check the communication lines for open or short circuit.

Q. Is the check result normal?

    Go to Step 9.
Repair the wiring harness.

STEP 9. Retest the system
Check whether you can operate the radio and CD player or the CD changer by using the steering wheel remote control switch.

Q. Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the radio and CD player or CD changer.