Inspection Procedure B-1

TECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU operates the ignition key reminder tone alarm function, based on input signals from the following switches:
- Ignition switch (IG1)
- Key reminder switch
- Driver's door switch

If the function does not work normally, a defect on the relevant circuit or the ETACS-ECU may be suspected.

TROUBLESHOOTING HINTS
- Malfunction of the key reminder switch
- Malfunction of the driver's door switch
- Malfunction of the ETACS-ECU
- Damaged harness wires or connectors

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.
If the ignition switch is at "LOCK" (OFF) position, do all of the following functions operate?
- Light reminder tone alarm function
- Central door locking system
- Hazard warning light
- Dome light dimming function
- Theft-alarm system

If none of the functions operate, check the ETACS-ECU battery circuit. Refer to Inspection Procedure P-1.
P - Charts

If any of the functions operate, go to Step 2.

STEP 2. Check the input signal.
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 "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.

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.
If one of the input signal checks shows a defect, check the relevant input circuit.
If no defect appears, replace the ETACS-ECU. The ignition key reminder tone alarm function should work normally.