Inspection Procedure 1

INSPECTION PROCEDURE 1: Steering Wheel Audio Remote Control Switch Does Not Function. [Vehicles With Radio And CD Player]

CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

Steering Wheel Audio Remote Control Switch Circuit (Part 1):

Steering Wheel Audio Remote Control Switch Circuit (Part 2):

TECHNICAL DESCRIPTION (COMMENT)
The power supply circuit to the steering wheel audio remote control switch, the steering wheel audio remote control switch, the radio and CD player, or the clock spring may be defective.

TROUBLESHOOTING HINTS
- The steering wheel audio remote control switch may be defective.
- The radio and CD player may be defective.
- The clock spring may be defective.
- Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool 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 remote control. Check whether the normal conditions listed below are displayed.







OK: Normal condition is displayed.

Q: Is the check result normal?

YES : Go to Step 9.

NO : Go to Step 2.

STEP 2. Check the steering wheel audio remote control switch.

Remove the steering wheel audio remote control switch. Then check continuity between the switch terminals.







Q: Is the steering wheel audio remote control switch in good condition?

YES : Go to Step 3.

NO : Replace the steering wheel audio remote control switch.

STEP 3. Check clock spring connector C-202 and C-205 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are clock spring connector C-202 and C-205 in good condition?

YES : Go to Step 4.

NO : Repair or replace the damaged component(s).

STEP 4. Check the clock spring.

Check whether the clock spring is in good condition (Refer to Driver's air bag module and clock spring). Testing and Inspection

Q: Is the check result normal?

YES : Go to Step 5.

NO : Replace the clock spring.

STEP 5. Check radio and CD player connector C-107 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is radio and CD player connector C-107 in good condition?

YES : Go to Step 6.

NO : Repair or replace the damaged component(s). The steering remote control switch should work normally.

STEP 6. Check the wiring harness between radio and CD player connector C-107 (terminal 22, 32) and clock spring connector C-205 (terminal 2, 3).

NOTE: Also check intermediate connector C-32 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-32 is damaged, repair or replace the connector.

- Check the communication lines for open and short circuit.

Q: Is the wiring harness between radio and CD player connector C-107 (terminal 22, 32) and clock spring connector C-205 (terminal 2, 3) in good condition?

YES : Go to Step 7.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

STEP 7. Check steering remote control switch connector C-213 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is steering remote control switch connector C-213 in good condition?

YES : Go to Step 8.

NO : Repair or replace the damaged component(s). The steering remote control switch should work normally.

STEP 8. Check the wiring harness between steering wheel audio remote control switch connector C-213 (terminal 2, 4) and clock spring connector C-202 (terminal 5, 4).

- Check the communication lines for open and short circuit.

Q: Is the wiring harness between steering remote control switch connector C-213 (terminal 2, 4) and clock spring connector C-202 (terminal 5, 4) in good condition?

YES : Go to Step 9.

NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary.

STEP 9. Retest the system

Check whether you can operate the radio and CD player by using the steering remote control.

Q: Is the check result normal?

YES : The trouble can be an intermittent malfunction.

NO : Replace the radio and CD player.