Inspection Procedure 2: SOS switch/information switch indicator light does not illuminate: Diagnosis

Required Special Tools 

• MB991223: Wiring harness set
• MB992006: Extra fine probe

1. STEP 1. Check the SOS switch/information switch indicator light. 

   Check that the SOS switch/information switch indicator light illuminates. Refer to ECALL & BCALL SWITCH  .

   Q: Is the check result normal? 

   YES:  Go to Step  2.

   NO:  Replace the ECALL & BCALL switch (Refer to ECALL & BCALL SWITCH  ).

2. STEP 2. Retest the system. 

   Q: Is the check result normal? 

   YES:  The trouble can be an intermittent malfunction (Refer to How to use Troubleshooting/inspection Service Points - HOW TO COPE WITH INTERMITTENT MALFUNCTION ).

   NO:  Replace the TCU (Refer to TCU  ).