Inspection Procedure E-3

Keyless Entry System: Encrypted Code cannot be Registered

Encrypted Transmitter Code Circuit:

CIRCUIT OPERATION
The ETACS-ECU operates the encrypted code register mode according to the following signals:
- Key reminder switch
- Hazard warning light switch

TECHNICAL DESCRIPTION (COMMENT)
Is the encrypted code register mode can not be set, the input circuits from the switches described in "CIRCUIT OPERATION" or the ETACS-ECU may be defective.

If the encrypted code register mode can be set but the transmitter can not be registered, 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
- MB991958: Scan Tool (MUT-III Sub Assembly)
- MB991824: Vehicles communication interface
- MB991827: MUT-III USB cable
- MB991911: MUT-III Main harness B

STEP 1. Check trouble symptom.

Q: Can the encrypted code register mode be set?

YES: Go to Step 3.

NO: Go to Step 2.

STEP 2. Check the input signal (by using the Pulse check mode of the monitor).
Check the input signals from the following switches:
- Key reminder switch
- Hazard warning light switch

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.




1. Connect scan tool MB991958. Refer to "How to connect SWS monitor." How to Connect SWS Monitor
2. Operate scan tool MB991958 according to the procedure below to display "Pulse check."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "Pulse Checking."

3. Check the scan tool MB991958 sounds or not.




4. If the switches (see the given table), which are applicable for the input signal check, are operated.

Q: When the key reminder switch and the hazard warning light switch are operated, does scan tool MB991958 sound in each case?

Buzzer of scan tool MB991958 sounds normally: Replace the ETACS-ECU. Check that the encrypted code can be registered in the transmitter.

Scan tool MB991958 does not sound when the ignition key is removed and reinserted: Refer to Inspection Procedure P-1 "ETACS-ECU does not receive a signal from the key reminder switch."

Scan tool MB991958 does not sound when the hazard warning light switch is turned from "OFF" to "ON": Refer to Inspection Procedure P-2 "ETACS-ECU does not receive a signal from the hazard warning light switch."

STEP 3. Check the transmitter.

Q: When the transmitter.s battery is replaced, can the encrypted code be registered?

YES: No action to be taken.

NO: Replace the transmitter. If the encrypted code can not be registered by means of the new transmitter, replace the ETACS-ECU. Check that the encrypted code can be registered in the transmitter.