INSPECTION PROCEDURE 1: Steering Wheel Audo Remote Control Switch does not Function. <Vehicles without 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

1. 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.
      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 radio and CD player or CD changer.

   NO  : Go to Step  2.

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 CHART
   
   

   Switch 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.

3. 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(s). Refer to HARNESS CONNECTOR INSPECTION . The steering remote control switch should work normally.

4. 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.

5. STEP 5. Check radio and CD player or CD changer connector C-104 for loose, corroded or damaged terminals, or terminals pushed back in the connector  .

   Q: Is radio and CD player or CD changer connector C-104 in good condition? 

   YES  : Go to Step  6.

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

6. STEP 6. Check the wiring harness between radio and CD player or CD changer connector C-104 (terminal 22, 32) and clock spring connector C-205 (terminal 2, 3)  .
   • Check the communication lines for open or short circuit.

   Q: Is the wiring harness between radio and CD player or CD changer connector C-104 (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.

7. 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(s). Refer to HARNESS CONNECTOR INSPECTION . The steering remote control switch should work normally.

8. 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.

9. STEP 9. Retest the system 

   Check whether you can operate the radio and CD player or the CD changer 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 radio and CD player or CD changer.