SEAT BELT WARNING SYSTEM TERMINALS OF ECU


  1. CHECK MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) AND INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


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

      A005A56E02
      Text in Illustration
      *A Main Body ECU (Multiplex Network Body ECU) with 1 connector *B for LHD
      *C for RHD - -
      *1 Main Body ECU (Multiplex Network Body ECU) *2 1 connector
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      Text in Illustration
      *A Main Body ECU (Multiplex Network Body ECU) with 3 connectors *B for LHD
      *C for RHD - -
      *1 Main Body ECU (Multiplex Network Body ECU) *2 3 connectors

    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 - Auxiliary battery power supply Power switch off 11 to 14 V
      MB-31 (ALTB) - Body ground - Auxiliary battery power supply Power switch off 11 to 14 V
      MB-32 (IG) - Body ground - Ignition power supply (IG signal) Power switch on (IG) → off 11 to 14 V → Below 1 V
      MB-29 (ACC) - Body ground - Ignition power supply (ACC signal) Power switch on (ACC) → off 11 to 14 V → Below 1 V
      MB-11 (GND1) - Body ground - Ground Always Below 1 Ω
      MB-18 (DBKL) - Body ground - Driver seat belt buckle switch signal Driver seat belt fastened 10 kΩ or higher
      MB-18 (DBKL) - Body ground - Driver seat belt buckle switch signal Driver seat belt unfastened Below 1 Ω
      L7-6 (LRCY) - Body ground G - Body ground Rear door courtesy light switch LH or RH input Rear door LH or RH closed (OFF) → open (ON) 10 kΩ or higher → Below 1 Ω

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

  2. CHECK COMBINATION METER SUB-ASSEMBLY


    1. Disconnect the L27 combination meter sub-assembly connector.

      A005D6XE02

    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
      L27-11 (ES) - Body ground BR - Body ground Ground Always Below 1 Ω
      L27-29 (SW) - Body ground R - Body ground Front passenger seat belt buckle switch signal Front passenger seat occupied, seat belt fastened 10 kΩ or higher
      L27-29 (SW) - Body ground R - Body ground Front passenger seat belt buckle switch signal Front passenger seat occupied, seat belt unfastened Below 1 Ω
      L27-38 (RLSB) - Body ground SB - Body ground Rear No. 1 seat belt LH buckle switch signal Rear No. 1 seat belt LH fastened 10 kΩ or higher
      L27-38 (RLSB) - Body ground SB - Body ground Rear No. 1 seat belt LH buckle switch signal Rear No. 1 seat belt LH unfastened Below 1 Ω
      L27-37 (RCSB) - Body ground L - Body ground Rear No. 1 seat belt center buckle switch signal Rear No. 1 seat belt center fastened 10 kΩ or higher
      L27-37 (RCSB) - Body ground L - Body ground Rear No. 1 seat belt center buckle switch signal Rear No. 1 seat belt center unfastened Below 1 Ω
      L27-36 (RRSB) - Body ground R - Body ground Rear No. 1 seat belt RH buckle switch signal Rear No. 1 seat belt RH fastened 10 kΩ or higher
      L27-36 (RRSB) - Body ground R - Body ground Rear No. 1 seat belt RH buckle switch signal Rear No. 1 seat belt RH unfastened Below 1 Ω
      L27-40 (RLBT) - Body ground W - Body ground Rear No. 2 seat belt LH buckle switch signal Rear No. 2 seat belt LH fastened 10 kΩ or higher
      L27-40 (RLBT) - Body ground W - Body ground Rear No. 2 seat belt LH buckle switch signal Rear No. 2 seat belt LH unfastened Below 1 Ω
      L27-39 (RRBT) - Body ground B - Body ground Rear No. 2 seat belt RH buckle switch signal Rear No. 2 seat belt RH fastened 10 kΩ or higher
      L27-39 (RRBT) - Body ground B - Body ground Rear No. 2 seat belt RH buckle switch signal Rear No. 2 seat belt RH unfastened Below 1 Ω

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

    3. Reconnect the L27 combination meter sub-assembly connector.

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

      Tester Connection Wiring Color Terminal Description Condition Specified Condition
      L27-1 (B) - Body ground L - Body ground Battery power supply Power switch off 11 to 14 V
      L27-2 (IG+) - Body ground BR - Body ground

      Ignition power supply

      (IG signal)

      		 Power switch off Below 1 V
      L27-2 (IG+) - Body ground BR - Body ground

      Ignition power supply

      (IG signal)

      		 Power switch on (IG) 11 to 14 V

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