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Inspection Procedure 2: Steering Wheel Audio Remote Control Switch does not Function. <Vehicles with MMCS>


caution Before replacing the audio visual navigation unit, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.






TECHNICAL DESCRIPTION (COMMENT)


The power supply circuit to the steering remote control switch, the steering remote control switch, the audio visual navigation unit, or the clock spring may be defective.

TROUBLESHOOTING HINTS



DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe

STEP 1. Check the remote controlled radio switch.


Remove the remote controlled radio switch. Then check continuity between the switch terminals.
Switch Position
 Tester Connection
 Measurement Value
No push
 2 - 4
 Approximately 71 kΩ
Mode
 Approximately 270 Ω
CH up
 Approximately 740 Ω
CH down
 Approximately 1.3 kΩ
VOL up
 Approximately 2.1 kΩ
VOL down
 Approximately 3.1 kΩ

Q. Is the remote controlled radio switch in good condition?

Go to Step 2.

Replace the remote controlled radio switch.

STEP 2. Check clock spring connector C-204 and C-205 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Are clock spring connector C-204 and C-205 in good condition?
Go to Step 3.
Repair or replace the damaged component (Refer to GROUP 00E, Harness Connector Inspection ). The steering remote control switch should work normally.

STEP 3. Check the clock spring.
Check whether the clock spring is in good condition (Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring <Except RALLIART>or <RALLIART>).

Q. Is the check result normal?
Go to Step 4.
Replace the clock spring.

STEP 4. Check audio visual navigation unit connector C-12 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is audio visual navigation unit connector C-12 in good condition?
Go to Step 5.
Repair or replace the damaged component (Refer to GROUP 00E, Harness Connector Inspection ). The steering remote control switch should work normally.

STEP 5. Check the wiring harness between audio visual navigation unit connector C-12 (terminal 53, 69) and clock spring connector C-205 (terminal 2, 3).

  • Check the communication lines for open and short circuit.
note Also check intermediate connector C-105 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-105 is damaged, repair or replace the connector as described in GROUP 00E, Harness Connector Inspection .

Q. Is the wiring harness between audio visual navigation unit connector C-12 (terminal 53, 69) and clock spring connector C-205 (terminal 2, 3) in good condition?
Go to Step 6.
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 6. Check steering remote control switch connector C-202 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q. Is steering remote control switch connector C-202 in good condition?
Go to Step 7.
Repair or replace the damaged component (Refer to GROUP 00E, Harness Connector Inspection ). The steering remote control switch should work normally.

STEP 7. Check the wiring harness between steering remote control switch connector C-202 (terminal 2, 4) and clock spring connector C-204 (terminal 5, 4).

  • Check the communication lines for open and short circuit.

Q. Is the wiring harness between steering remote control switch connector C-202 (terminal 2, 4) and clock spring connector C-204 (terminal 5, 4) in good condition?

    Go to Step 8.
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 8. Retest the system
Check whether you can operate the audio visual navigation unit by using the steering remote control.

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 audio visual navigation unit.