Inspection Procedure O-21

Transmitter:
- The "LOCK" switch signal is not sent to the ETACS-ECU.
- The "UNLOCK" switch signal is not sent to the ETACS-ECU.
- The "PANIC" switch signal is not sent to the ETACS-ECU.

Receiver And Transmitter Communication System:

CIRCUIT OPERATION
The ETACS-ECU receives an input signal from the transmitter through its built-in receiver, and evaluates the signal to operate various functions.

TECHNICAL DESCRIPTION (COMMENT)
The transmitter input signal is used to operate the following systems. If the signal fails, these systems will not work normally.
- Keyless entry system
- Theft-alarm system

TROUBLESHOOTING HINTS
- Malfunction of the transmitter
- Malfunction of the ETACS-ECU

DIAGNOSIS
Required Special Tools:
MB991223: Test Harness Set
MB991502: Scan Tool (MUT-II)
MB991529: Diagnostic Trouble Code Check Harness

STEP 1. Register the transmitter.
Register the transmitter (Refer to Keyless Entry System - On-vehicle Service - Encrypted Code Registration Method.)

If the transmitter is registered successfully, the transmitter input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

If the transmitter failed to be registered, go to Step 2.

STEP 2. Check the transmitter battery.
Measure the transmitter battery's voltage.
- Voltage should be approximately 2.5 - 3.2 volts.
If not approximately 2.5 - 3.2 volts, replace the battery. If the transmitter is registered successfully, the transmitter input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

If approximately 2.5 - 3.2 volts, go to Step 3.

STEP 3. Check the transmitter.
Use an other transmitter to register the secret code. (Refer to Keyless Entry System - On-vehicle Service - Encrypted Code Registration Method.)

If the transmitter is registered successfully, the transmitter input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.

If the transmitter tailed to be registered, replace the ETACS-ECU.

The transmitter input signal should be able to be checked and the functions, which are described in the "Technical Description (comment)," should work normally.