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."

CIRCUIT OPERATION
The ETACS-ECU operates the seat belt tone alarm function according to signals from the following switches:
- Ignition switch (IG1): ON
- Driver's seat belt switch: ON
- Vehicle speed signal: 8 km/h (5 mph) or more The ETACS-ECU operates the seat belt tone alarm function under the following conditions:
- Ignition switch (IG1): "ON" position
- Driver's seat belt: Unfastened
- Vehicle speed: 8 km/h (5 mph) or more

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
- Trouble in input signal system
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- The ETACS-ECU may be defective

DIAGNOSIS

Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: MUT-111 USB Cable
- MB991911: M.U.T.-III Main Harness B
- MB991813: SWS monitor kit
- MB991806: SWS monitor cartridge
- MB991812: SWS monitor harness (for column-ECU)
- MB991922: Probe harness

STEP 1. Use scan tool MB991958 to select "ECU COMM Check" 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. Connect special tool MB991911 before connecting special tool MB991812. Be sure to connect special tool MB991806 after turning on special tool MB991824.




1. Connect the special tool. Refer to "How to connect SWS monitor".
2. Turn the ignition switch to the "ON" position.
3. Operate scan tool MB991958 according to the procedure below to display "ECU COMM Check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "ECU COMM Check.
4. Scan tool MB991958 should show "OK" on the "ECU COMM Check" 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 scan tool MB991958 according to the procedure below to display "ETACS ECU."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Data List."
f. Select "ETACS ECU."




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

Q: Does the scan tool display "IG SW (IG1)" as normal condition?

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 side seat belt switch.




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 driver's seat belt is fastened, check if scan tool MB991958 sounds or not.

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

YES: Go to Step 4.

NO: Refer to Inspection Procedure O-3 "ETACS-ECU does not receive a signal from the driver's side 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. Check that the seat belt tone alarm function works normally.

NO: Refer to Inspection Procedure O-8 "ETACS-ECU does not receive a signal from the vehicle speed sensor."