Inspection Procedure 1

Inspection Procedure 1: No Navigation Screen is Displayed.

CAUTION: Before replacing the audio visual navigation unit, ensure that the power supply circuit, the ground circuit, and the communication circuit are normal. (Check that the voltage is 10 V or more.)

Audio Visual Navigation Unit Power Supply Circuit (Part 1):

Audio Visual Navigation Unit Power Supply Circuit (Part 2):

CAUTION: When the ignition switch is turned to the ACC position for 30 minutes with the EATCS-ECU function, the ACC power is cut-off automatically. For this function, the time to cut-off can be changed with ETACS system by the scan tool MB991958 or the MMCS operation. (Refer to [ETACS] or [MMCS]) Programming and Relearning

COMMENTS ON TROUBLE SYMPTOM
When the ignition switch is turned to the ACC or ON position, if the screen is not displayed at all, the power supply circuit or audio visual navigation unit may have a problem.

PROBABLE CAUSES
- Malfunction of power supply circuit
- Malfunction of audio visual navigation unit

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. Check audio visual navigation unit connector C-12, C-14 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio visual navigation unit connector C-14 in good condition?

YES : Go to Step 2.

NO : Repair or replace the damaged component(s).

STEP 2. Check the ground circuit to the audio visual navigation unit connector. Measure the resistance at audio visual navigation unit connector C-12, C-14.

1. Disconnect audio visual navigation unit connector C-12, C-14, and measure the resistance available at the wiring harness side of the connector.







2. Measure the resistance between audio visual navigation unit connector C-14 terminal 9 and ground.

OK: The resistance should be 2 ohms or less







3. Measure the resistance between audio visual navigation unit connector C-12 terminal 65 and ground.

OK: The resistance should be 2 ohms or less

Q: Is the measured resistance 2 ohms or less?

YES : Go to Step 4.

NO : Go to Step 3.

STEP 3. Check the wiring harness between audio visual navigation unit connector C-14 (terminal 9), C-12 (terminal 65) and ground.

- Check the ground wire for open circuit.

NOTE: Also check intermediate connector C-105, C-103 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-105, C-103 is damaged, repair or replace the connector as described.

Q: Is the wiring harness between audio visual navigation unit connector C-14 (terminal 9), C-12 (terminal 65) and ground in good condition?

YES : The trouble can be an intermittent malfunction.

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 4. Check ETACS-ECU connector C-317 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-317 in good condition?

YES : Go to Step 5.

NO : Repair or replace the damaged component(s).

STEP 5. Check the power supply circuit to the multivision display. Measure the voltage at multivision display connector C-14.

1. Disconnect the connector, and measure at the wiring harness-side connector.







2. Measure the voltage between multivision display connector C-14 terminal 17 and ground.

OK: Battery voltage

Q: Is the measured voltage battery voltage?

YES : Go to Step 7.

NO : Go to Step 6.

STEP 6. Check the wiring harness between ETACS-ECU connector C-317 (terminal 1) and audio visual navigation unit connector C-14 (terminal 17).

- Check the power supply line (battery supply) for open circuit and short circuit.

NOTE: Also check intermediate connector C-105 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-15 is damaged, repair or replace the connector as described.

Q: Is the wiring harness between ETACS-ECU connector C-317 (terminal 1) and audio visual navigation unit connector C-14 (terminal 17) 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 audio visual navigation unit connector C-13 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is audio visual navigation unit connector C-13 in good condition?

YES : Go to Step 8.

NO : Repair or replace the damaged component(s).

STEP 8. Check the power supply circuit to the multivision display. Measure the voltage at multivision display connector C-13.

1. Disconnect the connector, and measure at the wiring harness-side connector.







2. Measure the voltage between multivision display connector C-13 terminal 21 and ground.

OK: Battery voltage

Q: Is the measured voltage battery voltage?

YES : Go to Step 10.

NO : Go to Step 9.

STEP 9. Check the wiring harness between ETACS-ECU connector C-317 (terminal 1) and audio visual navigation unit connector C-13 (terminal 21).

- Check the power supply line (battery supply) for open circuit and short circuit.

NOTE: Also check intermediate connector C-103 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-103 is damaged, repair or replace the connector as described.

Q: Is the wiring harness between ETACS-ECU connector C-317 (terminal 1) and audio visual navigation unit connector C-13 (terminal 21) in good condition?

YES : Go to Step 10.

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 10. Using scan tool MB991958, check data list.

Check the input signal of ACC relay.

- Turn the ignition switch to the ACC position.







OK: Normal condition is displayed.

Q: Is the check result normal?

YES : Go to Step 11.

NO : Refer to ETACS, Diagnosis - Inspection Procedure 1 "The ignition switch (ACC) signal is not received." Inspection Procedure 1

STEP 11. Check ETACS-ECU connector C-309 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-309 in good condition?

YES : Go to Step 12.

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

STEP 12. Check the power supply circuit to the ETACS-ECU. Measure the voltage at ETACS-ECU connector C-309.

1. Disconnect the connector, and measure at the wiring harness-side connector.
2. Turn the ignition switch to the "ACC" position.







3. Measure the voltage between terminal 2 and ground.

OK: Battery voltage

Q: Is the measured voltage battery voltage?

YES : Go to Step 14.

NO : Go to Step 13.

STEP 13. Check the wiring harness between ETACS-ECU connector C-309 (terminal 2) and fusible link (37)

- Check the power supply line for open circuit and short circuit.

Q: Is the wiring harness between ETACS-ECU connector C-309 (terminal 2) and fusible link (37) in good condition?

YES : Go to Step 14.

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 14. Check ETACS-ECU connector C-315 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Is ETACS-ECU connector C-315 in good condition?

YES : Go to Step 15.

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

STEP 15. Check the wiring harness between audio visual navigation unit connector C-14 (terminal 14) and ETACS-ECU connector C-315 (terminal 9).

- Check the power supply line for open circuit and short circuit.

NOTE: Also check joint connector C-07 and intermediate connector C-105 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-07 or intermediate connector C-105 is damaged, repair or replace the connector as described.

Q: Is the wiring harness between audio visual navigation unit connector C-14 (terminal 14) and ETACS-ECU connector C-315 (terminal 9) in good condition?

YES : Go to Step 16.

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 16. Retest the system

Check if the audio visual navigation unit power is turned ON.

Q: Is the check result normal?

YES : The trouble can be an intermittent malfunction.

NO : Replace the audio visual navigation unit.