Inspection Procedure 2

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

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 remote control switch, the steering remote control switch, the audio visual navigation unit, or the clock spring may be defective.

TROUBLESHOOTING HINTS
- Malfunction of steering remote control switch
- Malfunctions of audio visual navigation unit
- Malfunction of the clock spring
- 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 : Replace the audio visual navigation unit.

NO : Go to Step 2.

STEP 2. Check the remote controlled radio switch.




Remove the remote controlled radio switch. Then check continuity between the switch terminals.






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

YES : Go to Step 3.

NO : Replace the remote controlled radio switch.

STEP 3. 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?

YES : Go to Step 4.

NO : Repair or replace the damaged component (Refer to general (electrical), Harness Connector Inspection). The steering remote control switch should work normally.

STEP 4. Check the clock spring.

Check whether the clock spring is in good condition (Refer to SRS, Air bag module and clock spring).

Q: Is the check result normal?

YES : Go to Step 5.

NO : Replace the clock spring.

STEP 5. 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?

YES : Go to Step 6.

NO : Repair or replace the damaged component (Refer to general (electrical), Harness Connector Inspection). The steering remote control switch should work normally.

STEP 6. Check the wiring harness between audio visual navigation unit connector C-12 (terminal 53, 69) and clock spring connector C-205 (terminal 2, 3).

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 general (electrical), Harness Connector Inspection.

- Check the communication lines for open or short circuit.

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?

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-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?

YES : Go to Step 8.

NO : Repair or replace the damaged component (Refer to general (electrical), Harness Connector Inspection). The steering remote control switch should work normally.

STEP 8. 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 or 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?

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 audio visual navigation unit by using the steering remote control.

Q: Is the check result normal?

YES : The trouble can be an intermittent malfunction (Refer to general (Body and Chassis), How to use Troubleshooting/inspection Service Points, How to Cope with Intermittent Malfunction).

NO : Replace the audio visual navigation unit.