Inspection Procedure 1

All of the Doors can not be Locked or Unlocked Using the Transmitter. (However, the Central Door Lock System Operates Normally.)






CIRCUIT OPERATION
The keyless entry receiver-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 keyless entry receiver-ECU
- Malfunction of the transmitter

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

STEP 1. Select a tester.

Q: Do you use scan tool MB991502?
YES: Go to Step 2.
NO: Go to Step 3.







STEP 2. Check the input signal (by pulse check).
Check the keyless entry receiver-ECU input signal by using scan tool MB991502.

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 (16-pin).
2. If the tone alarm of scan tool MB991502 sounds once when the transmitter's lock/unlock switches are operated, the keyless entry receiver-ECU input signal for switch circuits are normal.

Q: Is the input signal of transmitter normal?
YES: Go to Step 5.
NO: Go to Step 4.







STEP 3. Check the keyless entry receiver-ECU input signal (by using a voltmeter).
1. Use special tool MB991529 to connect a voltmeter between ground terminal 4 or 5 and the keyless entry receiver-ECU terminal 1 of the data link connector.
2. If a voltmeter indicator deflects once when transmitter's lock/unlock switches are operated, the keyless entry receiver-ECU input signal for that switch circuit system is normal.

Q: Is the input signal of transmitter normal?
YES: Go to Step 5.
NO: Go to Step 4.







STEP 4. Measure the voltage at transmitter battery.
1. Remove the transmitter battery.
2. Measure the transmitter battery's voltage.
- Voltage should be approximately 2.5 - 3.2 volts (battery positive voltage).

Q: Is the measured voltage approximately 2.5 - 3.2 volts?
YES: Go to Step 6.
NO: Replace transmitter battery, then go to Step 5.

STEP 5. Check the transmitter.
Use other transmitter to register the secret code.

Q: Does the lock/unlock switch operate normally?
YES: Replace the transmitter. Then go to Step 6.
NO: Replace the keyless entry receiver-ECU. Then go to Step 6.

STEP 6. Retest the system.

Q: Does the transmitter operate normally?
YES: The procedure is complete.
NO: Return to Step 1.