SEAT BELT WARNING SYSTEM TERMINALS OF ECU


  1. COMBINATION METER ASSEMBLY


    1. Disconnect the E46 combination meter assembly connector.

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    2. Measure the resistance according to the value(s) in the table below.

      Tech Tips

      Measure the values on the wire harness side with the connector disconnected.

      Tester Connection Wiring Color Terminal Description Condition Specified Condition
      E46-12 (PKBI) - Body ground L - Body ground Front passenger side seat belt buckle switch signal Front passenger side seat occupied, seat belt fastened 10 kΩ or higher
      E46-12 (PKBI) - Body ground L - Body ground Front passenger side seat belt buckle switch signal Front passenger side seat occupied, seat belt unfastened Below 1 Ω
      E46-30 (ET) - Body ground BR - Body ground Ground Always Below 1 Ω

      If the result is not as specified, there may be a malfunction in the wire harness.

    3. Reconnect the E46 combination meter assembly connector.

    4. Measure the voltage according to the value(s) in the table below.

      Tester Connection Wiring Color Terminal Description Condition Specified Condition
      E46-33 (IG+) - Body ground P - Body ground Power switch power supply Power switch off Below 1 V
      E46-33 (IG+) - Body ground P - Body ground Power switch power supply Power switch on (IG) 11 to 14 V
      E46-1 (WRNP) - Body ground BE - Body ground Front passenger side seat belt warning light signal Power switch on (IG), front passenger side seat occupied, seat belt fastened 11 to 14 V
      E46-1 (WRNP) - Body ground BE - Body ground Front passenger side seat belt warning light signal Power switch on (IG), front passenger side seat occupied, seat belt unfastened Alternates between 11 to 14 V and below 1 V

      If the result is not as specified, the combination meter assembly may have a malfunction.

  2. AIR CONDITIONING CONTROL ASSEMBLY


    1. Disconnect the E76 air conditioning control assembly connector.

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    2. Measure the resistance according to the value(s) in the table below.

      Tech Tips

      Measure the values on the wire harness side with the connector disconnected.

      Tester Connection Wiring Color Terminal Description Condition Specified Condition
      E76-5 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω

      If the result is not as specified, there may be a malfunction in the wire harness.

    3. Reconnect the E76 air conditioning control assembly connector.

    4. Measure the voltage according to the value(s) in the table below.

      Tester Connection Wiring Color Terminal Description Condition Specified Condition
      E76-2 (IG+) - Body ground B - Body ground Power switch power supply Power switch off Below 1 V
      E76-2 (IG+) - Body ground B - Body ground Power switch power supply Power switch on (IG) 11 to 14 V
      E76-9 (SIND) - Body ground BE - Body ground Front passenger side seat belt warning light signal Front passenger side seat occupied, seat belt fastened 11 to 14 V
      E76-9 (SIND) - Body ground BE - Body ground Front passenger side seat belt warning light signal Front passenger side seat occupied, seat belt unfastened Alternates between 11 to 14 V and below 1 V

      If the result is not as specified, the air conditioning control assembly may have a malfunction.

  3. MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)


    1. Disconnect the main body ECU (multiplex network body ECU) connectors.

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    2. Measure the resistance and voltage according to the value(s) in the table below.

      Tech Tips

      Measure the values on the wire harness side with the connector disconnected.

      Tester Connection Wiring Color Terminal Description Condition Specified Condition
      MB-30 (BECU) - Body ground - Battery power supply Power switch off 11 to 14 V
      MB-31 (ALTB) - Body ground - Battery power supply Power switch off 11 to 14 V
      MB-29 (ACC) - Body ground - ACC power supply Power switch off Below 1 V
      MB-29 (ACC) - Body ground - ACC power supply Power switch on (ACC) 11 to 14 V
      MB-11 (GND1) - Body ground - Ground Always Below 1 Ω
      MB-18 (DBKL) - Body ground - Driver side seat belt buckle switch signal Driver side seat belt fastened 10 kΩ or higher
      MB-18 (DBKL) - Body ground - Driver side seat belt buckle switch signal Driver side seat belt unfastened Below 1 Ω

      If the result is not as specified, there may be a malfunction in the wire harness.