Signals From Transmitter Switches Are Not Received

INPUT SIGNAL PROCEDURES

Signals From Transmitter Switches Are Not Received.

CAUTION: Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.

TECHNICAL DESCRIPTION (COMMENT)
Input signal from the keyless entry transmitter is used to operate the keyless entry system. If the signal is abnormal, the keyless entry system will not work normally.

TROUBLESHOOTING HINTS
- Battery discharged in the transmitter
- Malfunction of the transmitter
- Malfunction of WCM

DIAGNOSIS

Required Special Tools:
- MB992006: Extra fine probe
- MB991223: Harness set
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicles Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, read the diagnostic trouble code.

CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan toolMB991958.




1. Connect scan tool MB991958. Refer to "How to connect scan tool(M.U.T.-III)." Scan Tool Connecting

2. Turn the ignition switch to the "ON" position.
3. Check whether the WCM related DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the DTC set?

YES: Diagnose the WCM. Refer to Diagnostic Trouble Code Chart. Diagnostic Trouble Code Descriptions

NO: Go to Step 2.

STEP 2. Check the transmitter battery.






Measure the voltage of the transmitter battery.
- The value should be approximately 2.5 - 3.2 volts.

Q: Is the measured voltage approximately 2.5 - 3.2 volts?

YES: Go to Step 3.

NO: Replace the battery. If the transmitter can be registered normally, and operates normally, it indicates that the transmitter is sending normal signal to the WCM.

STEP 3. Register the keyless ID using a known-good transmitter of the same type again, and check the trouble symptom.

1. Register a known-good transmitter of the same type.
2. Check if the signals from the transmitter switches are received.

Q: Can the transmitter be registered correctly?

YES: Replace the original transmitter with a new one.

NO: Replace the WCM (Including when the new transmitter cannot be registered). Replace WCM and register the ID codes. (Refer to ID Codes Registration Procedure). If the transmitter works normally, the input signal from the transmitter should be normal.