Inspection Procedure B-3

Tone Alarm: Seat belt tone alarm function does not work normally.

Seat Belt Tone Alarm Function:

NOTE: This troubleshooting procedure requires the use of scan tool MB991958 and SWS monitor kit MB991813. For details on how to use the SWS monitor, refer to "How to use SWS monitor." How To Use SWS Monitor

CIRCUIT OPERATION
The ETACS-ECU operates this function in accordance with the input signals below.
- Ignition switch (IG1)
- Driver's seat belt switch

If this function does not work normally, these input signal circuit(s) or the ETACS-ECU may be defective.

TECHNICAL DESCRIPTION (COMMENT)
If the function does network normally, the input circuit system from the switches or the ETACS-ECU may be defective (refer to "CIRCUIT OPERATION").

TROUBLESHOOTING HINTS
- The driver's seat belt switch may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: MUT-III USB Cable
- MB991910: MUT-III Main Harness A
- MB991813: SWS monitor kit
- MB991806: SWS Monitor Cartridge
- MB991812: SWS Monitor Harness (For Column-ECU)
- MB991822: Probe Harness
- MB991854: SWS Monitor Harness (For 13-pin)

STEP 1. Use scan tool MB991958 to select "ECU COMM CHK" on the SWS monitor display.

Check the ETACS-ECU.

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 (16-pin).
2. Connect SWS monitor harness MB991854 to the data link connector (13-pin).
3. When the ignition switch is turned to the "ON" position.
4. Operate the scan tool MB991958 according to the procedure below to display "ECU COMM CHECK."
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "ECU COMM CHK".

5. Scan tool MB991958 should show "OK" on the "ECU COMM CHK" menu for the "ETACS ECU" menu.

Q: Is "OK" displayed on the "ETACS ECU" menu?

YES: Go to Step 2.

NO: Refer to Inspection Procedure A-3 "Communication with the ETACS-ECU is not possible."

STEP 2. Check the input signal by using "DATA LIST" menu of the SWS monitor.

Turn the ignition switch to the "ON" position before checking input signals from the ignition switch (IG1).




1. Operate the scan tool MB991958 according to the procedure below to display "ETACS ECU."
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "DATA LIST."
e. Select "ETACS ECU."




2. Check that normal conditions are displayed on the items described in the table.

Q: Is normal condition displayed on the "IG SW (IG1)"?

YES: Go to Step 3.

NO: Refer to Inspection Procedure N-2 "ETACS-ECU does not receive a signal from the ignition switch (IG1)."

STEP 3. Check the input signal (by using the pulse check mode of the monitor).

Check input signal from the driver's seat belt switch.




1. Operate the scan tool MB991958 according to the procedure below to display "PULSE CHECK."
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "PULSE CHECK."

2. When the driver's seat belt is unfastened, check if scan tool MB991958 sounds or not.

Q: Does scan tool MB991958 sound when the driver's side seat belt is unfastened?

YES: Go to Step 4.

NO: Refer to Inspection Procedure 0-3 "ETACS-ECU does not receive a signal from the driver's seat belt switch."

STEP 4. Check the input signal (by using the Pulse check mode of the monitor).

Check the input signals from the vehicle speed sensor.




1. Operate scan tool MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."

2. When the vehicle speed exceeds 10 km/h (6.2 mph), check that scan tool MB991958 sounds or not.

Q: Does scan tool MB991958 sound when the vehicle speed exceeds 10 km/h (6.2 mph)?

YES: Replace the ETACS-ECU. Verify that the seat belt tone alarm function works normally.

NO: Refer to Inspection Procedure 0-8 "ETACS-ECU does not receive vehicle speed signal".