Checking the control module for open-circuits

Fig 1: Identifying Ignition ON

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• Ignition off
• Remove the relay for heating the leak diagnostic pump
• Ignition on.

  Check the driver circuit for the relay coil for an open-circuit as follows: activate the relay driver. Measure the voltage between terminals #1 and #2 on the relay base.

  The voltage between terminals #1 and #2 should be battery voltage.

  If the value deviates excessively, check the voltage between terminal #2 and the battery and between terminal #1 and ground. Both should equal battery voltage.

  HINT: Do not forget to check that the power supply to the control module is OK. 

  Other information 

  • To access and replace the relay, see Central electronic module (CEM), replacing
  • See Checking wiring and terminals .
  Fig 2: Identifying VCT2000 Diagnostic Tool Symbol In VIDA

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  Fig 3: Identifying Terminals

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Was a fault detected? 

• YES 

  Refer to Verification 

• NO 

  Refer to Checking the control module for short-circuits