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Inspection Procedure 4

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

Steering Wheel Voice Control Switch Circuit (Part 1):




Steering Wheel 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 player or CD changer or audio visual navigation unit . Then, via the CAN communication, the signal is transmitted from the radio and CD player or CD changer or audio visual navigation unit to the hands-free module.

TROUBLE JUDGEMENT 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 player or 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 player or 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 wheel audio remote control switch.

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

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

YES : Go to Step 2.

NO : Diagnose the steering wheel audio remote control switch, or .) Symptom Chart

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

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.




1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. 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 Controller area network Diagnosis).

STEP 3. Check the steering wheel voice-control switch.







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






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

YES : Go to Step 4.

NO : Replace the steering wheel voice-control switch.

STEP 4. Check the steering wheel audio remote control switch.




Remove the steering wheel audio remote control switch. Then check continuity between the switch terminals.






Q: Is the steering wheel audio remote control switch in good condition?

YES : Go to Step 5.

NO : Replace the steering wheel audio remote control switch.

STEP 5. Check steering wheel voice-control switch connector C-209 and steering wheel audio remote control switch connector C-202 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are steering wheel voice-control switch connector C-209 and steering wheel audio remote control switch connector C-202 in good condition?

YES : Go to Step 6.

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

STEP 6. Check the wiring harness between steering wheel voice-control switch connector C-209 (terminal 3) and steering wheel audio remote control switch connector C-202 (terminal 3).

- Check the communication lines for open circuit and short circuit.

Q: Is the wiring harness between steering wheel voice-control switch connector C-209 (terminal 3) and steering wheel audio remote control switch connector C-202 (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 wheel voice-control switch connector C-209 (terminal 2) and clock spring connector C-204 (terminal 4).

- Check the communication lines for open circuit and short circuit.

Q: Is the wiring harness between steering wheel voice-control switch connector C-209 (terminal 2) and clock spring connector C-204 (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 wheel voice-control switch is operated.

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

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 radio and CD player or CD changer or audio visual navigation unit .