Inspection Procedure 22

INSPECTION PROCEDURE 22: Preset Stations are Erased.

Memory Backup Power Circuit (Part 1):

Memory Backup Power Circuit (Part 2):

CIRCUIT OPERATION
Power is continuously supplied to the radio and CD player or radio, CD player and CD changer.

TECHNICAL DESCRIPTION (COMMENT)
The cause is probably a faulty radio and CD player or radio, CD player and CD changer memory backup power supply system circuit.

TROUBLESHOOTING HINTS
- Damaged wiring harness or connector.
- Malfunction of the radio and CD player or radio, CD player and CD changer.

DIAGNOSIS

Required Special Tool:
- MB991223: Harness set

STEP 1. Measure at radio and CD player or radio, CD player and CD changer connector C-111 in order to check the power supply circuit to the radio and CD player or radio, CD player and CD changer (through the battery).







1. Disconnect radio and CD player or radio, CD player and CD changer connector C-111, and measure at the wiring harness side.







2. Measure the voltage between terminal number 11 and ground.
- The voltage should measure approximately 12 volts (battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery positive voltage)?

YES : Either repair or replace the radio and CD player or radio, CD player and CD changer. Check that a memory is retained.

NO : Go to Step 2.

STEP 2. Check radio and CD player or radio, CD player and CD changer connector C-111 for loose, corroded or damaged terminals, or terminals pushed back in the connector.







Q: Is radio and CD player or radio, CD player and CD changer connector C-111 in good condition?

YES : Go to Step 3.

NO : Repair or replace the component(s). Check that a memory is retained.

STEP 3. Check the wiring harness between radio and CD player or radio, CD player and CD changer connector C-111 (terminal 11) and the battery.







- Check the wiring harness for open circuit and short circuit.







NOTE: Also check intermediate connector C-29 and joint connector(1) C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connectors C-29 or joint connector(1) C-01 is damaged, repair or replace the connector.

Q: Is the wiring harness between radio and CD player or radio, CD player and CD changer connector C-111 (terminal 11) and the battery in good condition?

YES : Repair or replace the radio and CD player or radio, CD player and CD changer. Check that a memory is retained.

NO : Repair the wiring harness. Check that a memory is retained.