Inspection Procedure N-4

INSPECTION PROCEDURE N-4: Theft-alarm system: Panic alarm function does not work.

TECHNICAL DESCRIPTION (COMMENT)
If the keyless entry system is normal, the ETACS-ECU is defective.

TROUBLESHOOTING HINTS
- 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. Verify the keyless entry system.

Q: Does the keyless entry system work normally?

YES: Go to Step 2 or 3 .
NO: Solve the problem first.

STEP 2. Check the input signal (by using scan tool MB991502). Check the input signal from the transmitter "PANIC" 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.

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 panic alarm should work normally.
NO: Scan tool MB991502 does not sound when the transmitter panic switch is depressed: 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 3. Check the input signal (by using scan tool MB991502).

Check the input signals from the transmitter "PANIC" switch.
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 defects once when the input signal enters.

Q: Does the voltmeter indicator deflect?

YES: Replace the ETACS-ECU. The panic alarm should work normally.
NO: The voltmeter needle does not fluctuate when the transmitter panic switch is depressed: 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