Inspection Procedure B-1

Tone Alarm: Ignition key reminder tone alarm function does network normally.

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".

Ignition Key Reminder Tone Alarm Function:

CIRCUIT OPERATION
The ETACS-ECU operates the ignition key reminder tone alarm function (sounds the tone alarm intermittently), based on input signals from the following switches:
- Ignition switch (IG1): OFF
- Key reminder switch: OFF
- Driver's door switch: ON
The ETACS-ECU operates the ignition key reminder tone alarm function (sounds the tone alarm intermittently) if any of the following conditions are satisfied:
- Ignition switch: LOCK position (key inserted)
- Driver's door: OPEN

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: M.U.T.-III 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 "LOCK" (OFF) 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 "FUNCTION DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
- Ignition switch: OFF (key inserted)
- Driver's door: open
- Front passenger's door: closed




1. Operate scan tool MB991958 according to the procedure below to display "KEY RMND. ALM."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "BUZZER."
g. Select "KEY RMND. ALM."




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

NOTE: The scan tool MB991958 display changes when the driver's or the front passenger's door is opened. If any of the doors is open, the system cannot be checked correctly.

Q: Does the scan tool MB991958 display the items "IG SW (IG1)", "FRONT DOOR SW" and "BUZZER" as normal condition?

YES : Replace the ETACS-ECU. The ignition key reminder tone alarm function should now work normally.

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

NO : Refer to Inspection Procedure N-5 "The ETACS-ECU does not receive any signal from the front door switches."

NO : Go to Step 3.

STEP 3. Check the input signal (by using the Pulse check mode of the monitor).
Check the input signals from the key reminder switch.
- Ignition key: inserted in the ignition key cylinder




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. Check scan tool MB991958 sounds when the ignition key is removed.

Q: Does scan tool MB991958 sound when the ignition key is removed?

YES: Replace the ETACS-ECU. The ignition key reminder tone alarm function should now work normally.

NO: Refer to Inspection Procedure O-1 "The ETACS-ECU does not receive any signal from the key reminder switch."