Inspection Procedure 1

CIRCUIT OPERATION
Receiver within the ETACS-ECU receives the lock/unlock signal from the transmitter.

TECHNICAL DESCRIPTION (COMMENT)
The cause may be a malfunction of the receiver and transmitter communication system.

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

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

CAUTION: To prevent damage to the scan tool MB991502, make sure the ignition switch is "OFF" before connecting or disconnecting the scan tool MB991502.

STEP 1. Check the ETACS-ECU input signal.

Using either the scan tool or a voltmeter




- Using the scan tool MB991502
1. Connect scan tool MB991502 to the data link connector.
2. If the tone alarm of scan tool MB991502 sounds once when the transmitter's lock/unlock switches are operated, the ETACS-ECU input signal for that switch circuits are normal.




- Using a voltmeter
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and the ETACS-ECU terminal of the data link connector.
If a voltmeter indicator deflects once when the transmitter's lock/unlock switches are operated, the ETACS-ECU input signal for that switch circuit system is normal.
If the input signal of the transmitter is not normal, 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 (battery positive voltage).
If not approximately 2.5 - 3.2 volts, replace the battery. Then go to Step 4.
If approximately 2.5 - 3.2 volts, go to Step 3.

STEP 3. Check the transmitter.
Use other transmitter to register the secret code.
If lock/unlock switch operates normally, replace the transmitter. Then go to Step 4.
If lock/unlock switch does not operate normally, replace the ETACS-ECU.
Then go to Step 4.

STEP 4. Check symptom.
Confirm that the transmitter and ETACS-ECU are operating normally.