Inspection Procedure 1: Power of the radio and tape player does not turn ON when the ignition switch is in the "ACC" position or "ON" position: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. ETACS-ECU coding data check 
   1. Operate scan tool (M.U.T.-III) to read the ETACS-ECU option coding information (Refer to CODING TABLE ).
   2. Check that the "AUDIO" is set to "Present."

   Q: Is the check result normal? 

   • YES:  Go to Step 2.
   • NO:  Operate the scan tool (M.U.T.-III) to set the option coding "AUDIO" to "Present," and check the trouble symptom.
2. STEP 2. Using scan tool (M.U.T.-III), diagnose the CAN bus line 
   CAUTION: To prevent damage to scan tool (M.U.T.-III), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-III).
   1. Connect scan tool (M.U.T.-III). Refer to "HOW TO CONNECT THE SCAN TOOL (M.U.T.-III) ."
   2. Turn the ignition switch to the "ON" position.
   3. Diagnose the CAN bus line.
   4. Turn the ignition switch to the "LOCK" (OFF) position.

   Q: Is the CAN bus line found to be normal? 

   • YES:  Go to Step 3.
   • NO:  Repair the CAN bus line.
3. STEP 3. Using scan tool (M.U.T.-III), read the ETACS diagnostic trouble code. 

   Check if the DTC is stored in ETACS-ECU.

   Q: Is the DTC stored? 

   • YES:  Troubleshoot the ETACS-ECU. Refer to DIAGNOSTIC TROUBLE CODE CHART .
   • NO:  Go to Step 4.
4. STEP 4. Using scan tool (M.U.T.-III), check data list. 

   Check the input signal of ACC relay.

   • Turn the ignition switch to the ACC position.

     Item No.	Item name	Normal condition
     288	ACC switch	ON

     OK: Normal condition is displayed. 

   Q: Is the check result normal? 

   • YES:  Go to Step 5.
   • NO:  Refer to INSPECTION PROCEDURE 1: THE IGNITION SWITCH (ACC) SIGNAL IS NOT RECEIVED .
5. STEP 5. Check of short to power supply, short to ground, and open circuit in ACC line between radio and CD player connector and ETACS-ECU connector 

   Q: Is the check result normal? 

   • YES:  Go to Step 6.
   • NO:  Repair the connector(s) or wiring harness.
6. STEP 6. Voltage measurement at radio and CD player connector (+B2 terminal). 
   1. Disconnect the connector, and measure at the wiring harness side.
   2. Check the voltage between the radio and CD player connector (+B2 terminal) and ground.

      OK: The voltage should measure approximately 12 volts (battery positive voltage). 

   Q: Is the check result normal? 

   • YES:  Go to  Step 8.
   • NO:  Go to Step 7.
7. STEP 7. Check of short to power supply, short to ground, and open circuit in +B2 line between fusible link and radio and CD player connector 

   Q: Is the check result normal? 

   • YES:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
   • NO:  Repair the connector(s) or wiring harness.
8. STEP 8. Check of open circuit in GND2 line between radio and CD player connector and ground 

   Q: Is the check result normal? 

   • YES:  Go to Step 9.
   • NO:  Repair the connector(s) or wiring harness.
9. STEP 9. Check that the radio and CD player is correctly ground 

   The radio and CD player should be connected to the ground with an assembling screw.

   Q: Is the radio and CD player correctly ground? 

   • YES:  Go to Step 10.
   • NO:  Securely install and ground the radio and CD player.
10. STEP 10. Retest the system 

    Check if the radio and CD player power is turned ON.

    Q: Is the check result normal? 

    • YES:  The trouble can be an intermittent malfunction (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTION ).
    • NO:  Replace the radio and CD player.