Inspection Procedure 5: SOS switch does not respond (It does not start calling to the telematics call center): Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB992006: Extra Fine Probe

1. STEP 1. Check the SOS switch. 

   Measure the resistance the SOS switch/information switch during operation/non-operation. 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. Resistance measurement at the TCU connector (SW1+ terminal). 
   1. Disconnect the TCU connector, and measure at the wiring harness side.
   2. Measure the resistance between the TCU connector (SW1+ terminal) and ECALL & BCALL switch connector (terminal No. 11).

      OK: The resistance should be 2 ohms or less 

      Q: Is the check result normal? 

      YES:  Go to Step  3.

      NO:  Repair the connector(s) or wiring harness.

3. STEP 3. 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  ).