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) Refer to Harness Connector Inspection 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

NOTE: Also check intermediate connector C-29 and joint con-nector1 C-01 for loose, corroded, or damaged terminals, or terminals pushed back in the connector If intermediate connectors C-29 or joint connector1 C-01 is damaged, repair or replace the connector as described in Harness Connector Inspection

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