Inspection Procedure B-1

Tone Alarm: Ignition key reminder tone alarm function does not work normally.

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 not work normally, the input circuit system from the switches or the ETACS-ECU may be defective (refer to "CIRCUIT OPERATION").

TROUBLESHOOTING HINTS
- The key reminder switch may be defective
- The front door switches 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
- MB991911: MUT-III Main Harness B
- MB991862: SWS monitor kit

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. Connect the DLC harness before connecting the column-ECU harness. Be sure to connect SWS monitor kit MB991862 after turning on scan tool MB991958.







1. Connect scan tool MB991958 to the data link connector.
2. Connect SWS monitor kit MB991862 to the column switch connector.
3. Turn the ignition switch to the "LOCK" (OFF) position.
4. Operate scan tool MB991958 according to the procedure below to display "ECU COMM CHK."
1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. 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 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







Operate scan tool MB991958 according to the procedure below to display "KEY RMND. ALM."
1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "SWS MONITOR."
4. Select "FUNCTION DIAG."
5. Select "BUZZER."
6. Select "KEY RMND. ALM."




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

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

Q: Are normal conditions displayed on the "IG SW (IG1)", "FRONT DOOR SW" and "BUZZER"?

Normal conditions are displayed for all the items:
Replace the ETACS-ECU. The ignition key reminder tone alarm function should now work normally.

The scan tool does not show the respective normal condition for item "IG SW (IG1).": Refer to Inspection Procedure N-2 "ETACS-ECU does not receive a signal from the ignition switch (IG1)."

The scan tool does not show the respective normal condition for item "FRONT DOOR SW.": Refer to Inspection Procedure N-4 "ETACS-ECU does not receive a signal from the driver's or the front passenger's door switch."

The scan tool does not show the respective normal condition for item "BUZZER.": 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.
Operate scan tool MB991958 according to the procedure below to display "PULSE CHECK."
1. Select "SYSTEM SELECT."
2. Select "SWS."
3. Select "PULSE CHECK."
- Check whether scan tool MB991958 sounds or not when the ignition key is removed and reinserted.

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

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

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