INSPECTION PROCEDURE 2: Steering Wheel Audio Remote Control Switch does not Function. <Vehicles with MMCS>: 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.
- Turn the ignition switch to "ON" position.
- Operate each switch of the steering remote control. Check whether the normal conditions listed below are displayed.TERMINALS REFERENCE CHART
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?
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.
SWITCH POSITION TESTER CONNECTION CHARTSwitch Position Tester Connection Measurement Value No push 2 - 3 Approximately 3.1 kΩ 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?
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 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 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 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 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 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 HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
NO : Replace the audio visual navigation unit.