Inspection Procedure E-1
INSPECTION PROCEDURE E-1: Keyless Entry System: Keyless entry system does not operate.
CIRCUIT OPERATION
Receiver within the ETACS-ECU receives the lock/ unlock/trunk signal from the transmitter.
TECHNICAL DESCRIPTION (COMMENT)
The cause may be a malfunction of the receiver and transmitter communication system.
TROUBLESHOOTING HINTS
- The ETACS-ECU may be defective.
- The transmitter may be defective.
DIAGNOSIS
Required Special Tools:
- MB991223: Test Harness Set
- MB991502: Scan Tool (MUT-II)
- MB991529: Diagnostic Trouble Code Check Harness.
STEP 1. Check the central door locking system operation.
Q: Does the central door locking system work normally?
YES : Go to Step 2
NO : Carry out the troubleshooting by referring the Symptom Chart.
STEP 2. Check the input signal (by using scan tool MB991502).
Check the input signals from the transmitter switches.
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. All the doors should be locked or unlocked by using the transmitter.
NO : Scan tool MB991502 does not sound when the transmitter switch "LOCK", "UNLOCK" or "TRUNK" button is depressed: Refer to Inspection Procedure O-17 "The lock, unlock, trunk or panic 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 transmitter switches.
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. All the doors should be locked or unlocked by using the transmitter.
NO : The voltmeter needle does not fluctuate when the transmitter switch "LOCK", "UNLOCK" or "TRUNK" button is depressed: Refer to Inspection Procedure O-17 "The lock, unlock, trunk or panic switch signal is not sent to the ETACS-ECU