Inspection Procedure E-4
Keyless entry system: Encrypted code cannot be registerTECHNICAL DESCRIPTION (COMMENT)
The ETACS-ECU activates the encrypted code register mode according to the following switch signals:
- Key reminder switch
- Hazard warning light switch
If the encrypted code register mode is not set, the relevant input signal circuit or the ETACS-ECU may be detective.
If a transmitter can not be registered although the encrypted code register mode is set, the transmitter or the ETACS-ECU may be defective.
TROUBLESHOOTING HINTS
- Malfunction of the key reminder switch
- Malfunction of the hazard warning light switch
- Malfunction of the transmitter
- 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 trouble symptom.
Q: Is the encrypted code register mode set?
YES: Go to Step 4.
NO: Go to Step 2
STEP 2. Check the input signal (by using scan tool MB991502).
Check the input signals from the following switches:
- Key reminder switch
- Hazard warning light 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. Check that the transmitter can be registered.
NO: Check the relevant input circuit.
STEP 3. Check the input signal (by using a voltmeter).
Check the input signals from the following switches:
- Key reminder switch
- Hazard warning light 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 deflects once when the input signal enters.
Q: Does the voltmeter indicator deflect?
YES: Replace the ETACS-ECU. Check that the transmitter can be registered.
NO: Check the relevant input circuit.
STEP 4. Check the transmitter.
Q: Can the encrypted code be registered when the transmitter battery has been renewed?
YES: There is no action to be taken.
NO: Replace the transmitter. If the transmitter can not be registered even if the transmitter has been replaced, replace the ETACS-ECU. Check that the transmitter can be registered.