Inspection Procedure B-2

Tone Alarm: Light Reminder Tone Alarm Function does not Work Normally

Light Reminder Tone Alarm Function:

NOTE: This troubleshooting requires use of scan tool MB991502 and SWS monitor kit MB991862. For details of how to use the SWS monitor, refer to "How to use SWS monitor".

CIRCUIT OPERATION

The ETACS-ECU operates the light reminder tone alarm function intermittently according to the following signals:
- Ignition switch (IG1): OFF
- Front door switch (LH): ON
- Taillight switch; ON
- Headlight switch: ON

The ETACS-ECU operates the light reminder tone alarm function intermittently under the following conditions.
- ignition switch: LOCK position (key removed)
- Driver's door: OPEN
- Lighting Switch: Tailor Head position

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
- Malfunction of front door switches
- Malfunction of column switch (turn-signal light and lighting switch)
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

DIAGNOSIS

Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991862: SWS monitor kit







STEP 1. Use scan tool to select "ECU CHECK" on the SWS monitor display.

Check the following ECUs:
- ETACS-ECU
- column-ECU

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502. Also connect SWS monitor kit MB991862 after turning on scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Connect SWS monitor kit MB991862 to the column switch connector.
3. When the ignition switch is turned to the "LOCK" (OFF) position, scan tool MB991502 should show "OK" on the "ECU CHECK" menu.

Q: Are "OK" displayed on the "ETACS-ECU" and "COLUMN ECU"?
"OK" are displayed for all the items : Go to STEP 2.
"NG" is displayed on the "ETACS ECU" menu : Refer to Inspection Procedure A-3 "Communication with ETACS-ECU is impossible."
"NG" is displayed on the "COLUMN ECU" menu : Refer to Inspection Procedure A-2 "Communication with column switch (column-ECU) is impossible."

STEP 2. Check the input signal by using service data of the SWS monitor.







Check the input signals from the following switches:
- ignition switch: OFF (key removed)
- lighting switch: TAIL or HEAD
- Driver's door: open




Select "BUZZER-LGT MONI. ALRM" (FUNCTION DIAG.), and check that normal conditions are displayed on the items described in the table above.

Q: Are normal conditions displayed for "HEADLIGHT SW", "TAILLIGHT SW", "IG SW IG1", "FRONT DOOR SW", "H/L AUTO-CUT" and "BUZZER"?

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

NO:
- Normal condition is not displayed on the "HEADLIGHT SW: Refer to Inspection Procedure L-5 "ETACS-ECU does not receive a signal from the headlight switch."
- Normal condition is not displayed on the "TAILLIGHT SW": Refer to Inspection Procedure L-5 "ETACS-ECU does not receive a signal from the taillight switch."
- Normal condition is not displayed on the "IG SW IG1": Refer to Inspection Procedure L-2 "ETACS- ECU does not receive a signal from the ignition switch (IG1)."
- Normal condition is not displayed on the "FRONT DOOR SW: Refer to Inspection Procedure L-5 "ETACS-ECU does not receive a signal from the driver's or the front passenger's door switch."
- Normal condition is not displayed on the "H/L AUTO-CUT": Refer to Inspection Procedure I-8 "Headlight automatic shutdown function does not work normally."
- Normal condition is not displayed on the "BUZZER": Replace the ETACS-ECU. The light reminder tone alarm function should work normally.