Inspection Procedure N-1
INSPECTION PROCEDURE N-1: Theft-alarm system: Theft-alarm system is not armed (security indicator light does not illuminate).
Connectors:
CIRCUIT OPERATION
The theft-alarm system will be armed after the doors are locked and then the security indicator light has illuminated for approximately 18 seconds.
TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU arms the theft-alarm system according to the input signals from the following switches:
- Ignition key reminder switch
- Driver's and passenger's door switch
- Driver's and passenger's door key cylinder switch
- Driver's and front passenger's door lock actuator switch
- Trunk lid latch switch
- Transmitter
If the theft-alarm system is armed normally, the relevant input signal circuit(s), the theft-alarm indicator light or the ETACS-ECU may be defective.
TROUBLESHOOTING HINTS
- The combination meter (security indicator light bulb or printed-circuit board) may be defective
- The driver's or passenger's door switch may be defective
- The driver's or passenger's door lock key cylinder switch may be defective
- The driver's or passenger's door lock actuator switch may be defective
- The trunk lid latch switch may be defective
- The transmitter 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: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness.
STEP 1. Check the ETACS-ECU power supply circuit.
Check that the hazard warning light illuminate when the ignition switch is in the 'LOCK' (OFF) position.
Q: Does the hazard warning light illuminate?
YES : Go to Step 2 .
NO : Check the ETACS-ECU battery circuit. Refer to Inspection Procedure P-1. Inspection Procedure P-1
STEP 2. Check the security indicator circuit at the ETACS-ECU connector C-318.
1. Disconnect the ETACS-ECU connector C-318 and measure at the wiring harness side.
2. Connect terminal 74 to the ground.
Q: Does the security indicator light illuminate?
YES : Go to Step 10
NO : Go to Step 3 .
STEP 3. Check the security indicator light bulb.
Q: Is the security indicator light bulb in good condition?
YES : Go to Step 4 .
NO : Replace it. The security indicator light should illuminate, and the theft-alarm system should be armed normally.
STEP 4. Check the combination meter (printed-circuit board).
1. Remove the combination meter.
2. Remove the seat belt warning light bulb. The measure the resistance between the bulb terminals.
3. Install the bulb to the combination meter, and then measure the resistance between connector C-101 terminal 1 and 47. The resistance reading at this time should be much the same as the resistance measured at Step (2).
Q: Are the two resistance values extremely different each other?
YES : Repair or replace the combination meter (printed-circuit board). The security indicator light should illuminate, and the theft-alarm system should be armed normally.
NO : Go to Step 5.
STEP 5.Check the battery power supply circuit to the combination meter. Test at combination meter connector C-101.
1. Disconnect the combination meter connector C-101 and measure the voltage available at the wiring harness side of the connector.
2. Measure the voltage between terminal 32 and ground.
- The voltage should equal approximately 12 volts (battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery positive voltage)?
YES : Go to Step 8 .
NO : Go to Step 6.
STEP 6. Check the combination meter connector C-101 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
Q: Is combination meter connector C-101 in good condition.
YES : Go to Step 7.
NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. Diagnostic AidsThe security indicator light should illuminate, and theft-alarm system should be armed normally.
STEP 7. Check the wiring harness between combination meter connector C-101 and battery.
NOTE: Also check joint connector C-141 and intermediate connector C-209 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If joint connector C-141 and intermediate connector C-209 are damaged, repair or replace the damaged components) as described in Harness Connector Inspection. Inspection Procedure O-17
Q: Are the wiring harness between combination meter connector C-101 and battery in good condition?
YES : No action is necessary and testing is complete.
NO : Repair or replace them. The security indicator light should illuminate, and the theft-alarm system should be armed normally.
STEP 8. Check the combination meter connector C-102 and ETACS-ECU connector C-318 for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Are combination meter connector C-102 and ETACS-ECU connector C-318 in good condition?
YES : Go to Step 9.
NO : Repair or replace the damaged component(s). Refer to Harness Connector Inspection. The security indicator light should illuminate, and the theft-alarm system should be armed normally.
STEP 9. Check the wiring harness between combination meter connector C-102 and ETACS-ECU connector C-318.
Q: Is the wiring harness between combination meter connector C-102 (terminal 47) and ETACS-ECU connector C-318 (terminal 74) in good condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the connector(s) may have loose, corroded or damaged terminals, or terminals pushed back in the connector. Repair the wiring harness as necessary. The security indicator light should illuminate, and the theft-alarm system should be armed normally.
STEP 10. Check the input signal (by using scan tool MB991502).
Check the input signals from the following switches:
- Ignition key reminder switch
- Driver's door switch
- Driver's and passenger's door key cylinder switch
- Driver's and front passenger's door lock actuator switch
- Trunk lid latch switch
- Transmitter
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.
1. Connect scan tool MB991502 to the data link connector.
2. Check that the tone alarm of scan tool MB991502 sounds when the input signal enters.
Q: Does the tone alarm of scan tool MB991502 sound when the input signal enters?
YES : Replace the ETACS-ECU. The security indicator light should illuminate, and the theft-alarm system should be armed normally.
NO :
- Scan tool MB991502 does not sound when the ignition key is inserted and then removed: Refer to Inspection Procedure O-3 "The key reminder switch signal is not sent to the ETACS-ECU." Inspection Procedure O-3
- Scan tool MB991502 does not sound when the driver's door is opened: Refer to Inspection Procedure O-8 "The driver's or passenger's door switch signal is not sent to the ETACS-ECU." Inspection Procedure O-8
- Scan tool MB991502 does not sound when each of the driver's and passenger's door is unlocked by using the ignition key: Refer to Inspection Procedure O-9 "The driver's and passenger's door key cylinder switch signal is not sent to the ETACS-ECU." Inspection Procedure O-9
- Scan tool MB991502 does not sound when each of the driver's and passenger's door is unlocked by using the inside lock knob: Refer to Inspection Procedure O-10 "The driver's or passenger's door lock actuator switch signal is not sent to the ETACS-ECU." Inspection Procedure O-10
- Scan tool MB991502 does not sound when the trunk lid is opened: Refer to Inspection Procedure O-12 "The trunk lid latch switch signal is not sent to the ETACS-ECU." Inspection Procedure O-12
- Scan tool MB991502 does not sound when the doors are locked and unlocked by using the transmitter: Refer to Inspection Procedure O-17 "The lock, unlock, trunk or panic switch signal is not sent to the ETACS-ECU." Inspection Procedure O-17
STEP 11. Check the input signal (by using scan tool voltmeter).
Check the input signals from the following switches:
- Ignition key reminder switch
- Driver's door switch
- Driver's and passenger's door key cylinder switch
- Driver's and front passenger's door lock actuator switch
- Trunk lid latch switch
- Transmitter
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
2. Check that the voltmeter indicator deflects once when the input signal enters.
Q: Does the voltmeter indicator deflect?
YES : Replace the ETACS-ECU. The security indicator light should illuminate, and the theft-alarm system should be armed normally.
NO :
- The voltmeter needle does not fluctuate when the ignition key is inserted and then removed: Refer to Inspection Procedure O-3 "The key reminder switch signal is not sent to the ETACS-ECU." Inspection Procedure O-3
- The voltmeter needle does not fluctuate when the driver's door is opened: Refer to Inspection Procedure O-8 "The driver's or passenger's door switch signal is not sent to the ETACS-ECU." Inspection Procedure O-8
- The voltmeter needle does not fluctuate when each of the driver's and passenger's door is unlocked by using the ignition key: Refer to Inspection Procedure O-9 "The driver's and passenger's door key cylinder switch signal is not sent to the ETACS-ECU." Inspection Procedure O-9
- The voltmeter needle does not fluctuate when each of the driver's and passenger's door is unlocked by using the inside lock knob: Refer to Inspection Procedure O-10 "The driver's or passenger's door lock actuator switch signal is not sent to the ETACS-ECU." Inspection Procedure O-10
- The voltmeter needle does not fluctuate when the trunk lid is opened: Refer to Inspection Procedure O-12 "The trunk lid latch switch signal is not sent to the ETACS-ECU." Inspection Procedure O-12
- The voltmeter needle does not fluctuate when the doors are locked and unlocked by using the transmitter: Refer to Inspection Procedure O-17 "The lock, unlock, trunk or panic switch signal is not sent to the ETACS-ECU." Inspection Procedure O-17