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Inspection Procedure 5: SOS switch does not respond (It does not start calling to the telematics call center).
 
 
cautionWhen replacing the ECU, always check that the communication circuit is normal.
 
 
TECHNICAL DESCRIPTION (COMMENT)
If the SOS switch does not respond (It does not start calling to the telematics call center), there is a possibility that a defect in the SOS switch or a defect in the TCU.
 
 
TROUBLESHOOTING HINTS
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
  • The ECALL&BCALL switch may be defective
  • The TCU may be defective
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Check the SOS switch.
Measure the resistance the SOS switch/information switch during operation/non-operation. Refer to .
Is the check result normal?
Go to Step 2.
Replace the ECALL&BCALL switch (Refer to ).
 
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
Is the check result normal?
Go to Step 3.
Repair the connector(s) or wiring harness.
 
STEP 3. Retest the system.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the TCU (Refer to ).