INSPECTION PROCEDURE B-1: Tone Alarm: Ignition key reminder tone alarm function does not work normally.: 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 illuminates when the ignition switch is in the "LOCK" (OFF) position.
Q: Does the hazard warning light illuminate?
YES : Go to Step 2 < when using scan tool MB991502 > or 3 < when using a voltmeter >.
NO: Check the ETACS-ECU battery circuit. Refer to INSPECTION PROCEDURE P-1 .
- STEP 2. Check the input signal (by using scan tool MB991502).
Check the input signals from the following switches:
- Ignition switch (IG1)
- Key reminder switch
- Driver's door switch
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.- Connect scan tool MB991502 to the data link connector.
- 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 ignition key reminder tone alarm function should work normally.
NO :
- Scan tool MB991502 does not sound when the ignition switch is turned from "ACC" to "ON": Refer to INSPECTION PROCEDURE O-2 "THE IGNITION SWITCH (IG1) SIGNAL IS NOT SENT TO THE ETACS-ECU ."
- 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 ."
- 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 ."
- STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the following switches:
- Ignition switch (IG1)
- Key reminder switch
- Driver's door switch
- Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and ETACS-ECU terminal 9 of the data link connector.
- Check that the voltmeter indicator deflects once when the input signal enters.
Q: Does the voltmeter indicator deflect?
YES : Replace the ETACS-ECU. The ignition key reminder tone alarm function should work normally.
NO :
- The voltmeter needle does not fluctuate when the ignition switch is turned from "ACC" to "ON": Refer to INSPECTION PROCEDURE O-2 "THE IGNITION SWITCH (IG1) SIGNAL IS NOT SENT TO THE ETACS-ECU ."
- 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 ."
- 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 ."