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Inspection Procedure 4

Inspection Procedure 4: Even when the steering voice-control switch is operated, the conversation is not possible.

Steering Voice Control Switch Circuit:




Steering Voice Control Switch Circuit Part 1:




Steering Voice Control Switch Circuit Part 2:






FUNCTION
When the steering wheel voice-control switch is operated, the switch signal is transmitted to the radio and CD changer or audio visual navigation unit . Then, via the CAN communication, the signal is transmitted from the radio and CD changer or audio visual navigation unit to the hands-free module.

TROUBLE JUDGMENT CONDITIONS
If the conversation is not possible even when the steering wheel voice-control switch is operated, the steering wheel voice-control switch or radio and CD changer or the audio visual navigation unit may be defective.

TROUBLESHOOTING HINTS
- Malfunction of the steering wheel voice-control switch
- Malfunction of the hands-free module
- Malfunction of the radio and CD changer or audio visual navigation unit
- Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe

STEP 1. Check the steering audio switch.

Check that the radio and CD changer or audio visual navigation unit can be operated normally using the steering audio switch.

Q: Is it possible to normally operate the radio and CD changer or audio visual navigation unit using the steering audio switch?

YES: Go to Step 2.

NO: Diagnose the steering audio switch. Refer to Audio and Navigation System - Radio and CD player - Diagnosis or MMCS - Diagnosis .)




STEP 2. Using scan tool MB991958, diagnose the CAN bus line.

Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)."
1. Turn the ignition switch to "ON" position.
2. Diagnose the CAN bus line.
3. Turn the ignition switch to "LOCK" (OFF) position.

Q: Is the CAN bus line found to be normal?

YES: Go to Step 3.

NO: Repair the CAN bus line. (Refer to Information Bus, Troubleshooting.)










STEP 3. Check the steering voice-control switch.

Remove the steering voice-control switch. Then check continuity between the switch terminals.

Q: Is the steering voice-control switch in good condition?

YES: Go to Step 4.

NO: Replace the steering voice-control switch.







STEP 4. Check the steering audio switch.

Remove the steering audio switch. Then check continuity between the switch terminals.

Q: Is the steering audio switch in good condition?

YES: Go to Step 5.

NO: Replace the steering audio switch.

STEP 5. Check steering voice-control switch connector C-206 and steering audio switch connector C-213 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are steering voice-control switch connector C-206 and steering audio switch connector C-213 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.

STEP 6. Check the wiring harness between steering voice control switch connector C-206 (terminal 3) and steering audio switch connector C-213 (terminal 3).

Check the communication lines for open circuit and short circuit.

Q: Is the wiring harness between steering voice-control switch connector C-206 (terminal 3) and steering audio switch connector C-213 (terminal 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 the wiring harness between steering voice control switch connector C-206 (terminal 2) and clock spring connector C-202 (terminal 4).

Check the communication lines for open circuit and short circuit.

Q: Is the wiring harness between steering voice-control switch connector C-206 (terminal 2) and clock spring connector C-202 (terminal 4) in good condition?

YES: Go to Step 8.

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 8. Retest the system

Check that the hands-free cellular phone system works normally when the steering voice-control switch is operated.

Q: Check that the hands-free cellular phone system works normally when the steering voice-control switch is operated.

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

NO: Replace the radio and CD changer or audio visual navigation unit .