Inspection Procedure C-6
Central Door Locking System: Forgotten key prevention function does not work normally.Forgotten Key Prevention Function Circuit:
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
If the key reminder buzzer function does not work normally, the input signal circuits below or the ETACS-ECU may be defective.
- Key reminder switch
- Driver's or front passenger's door switch
- Driver's door lock actuator
TECHNICAL DESCRIPTION (COMMENT)
If the forgotten key prevention function does not work normally, the input circuit from the switches or the ETACS-ECU may be defective.
TROUBLESHOOTING HINTS
- The key reminder switch may be defective
- The driver's or front passenger's door switch may be defective
- The driver's door lock actuator 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 the scan tool MB991958 to the data link connector (16-pin).
2. Connect the SWS monitor harness MB991854 to the data link connector (13-pin).
3. Turn the ignition switch to the "LOCK" (OFF) position.
4. Operate the scan tool MB991958 as follows:
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "SWS MONITOR."
d. Select "ECU COMM CHK".
5. Check the scan tool MB991958 should show "OK" on 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.
Check the input signals from the switches in the following conditions:
- Open the driver's door. (The front door switch (LH) is turned to the ON position.)
- Close the front passenger's door. (The front door switch (RH) is turned to the OFF position.)
1. Operate the scan tool MB991958 as follows:
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 given.
Q: The scan tool show the respective normal condition for item "FRONT DOOR SW."
YES: Go to Step 3.
NO: Refer to Inspection Procedure N-5 "ETACS-ECU does not receive signals from the front door switches."
STEP 3. Check the input signal (by using the pulse check mode of the monitor).
Check the input signals from the following switches:
- Key reminder switch
- Driver's door lock actuator switch
1. Operate the scan tool MB991958 as follows:
a. Select "SYSTEM SELECT."
b. Select "SWS."
c. Select "PULSE CHECK."
2. If the switches (see table given), which are applicable for the input signal check, are operated, verify if scan tool MB991958 sounds or not.
Q: Does scan tool MB991958 sound whenever the key reminder switch and the driver's door lock actuator switch are operated?
YES
NO
NO