SEAT BELT WARNING SYSTEM(w/o Occupant Classification System) TERMINALS OF ECU


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

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    *A for LHD *B for RHD

    1. Disconnect the instrument panel junction block assembly and main body ECU (multiplex network body ECU) connectors.

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    2. Reconnect the instrument panel junction block assembly connectors.

    3. 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.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      MB-31 (BECU) - Body ground - Battery power supply Always 11 to 14 V
      MB-32 (IG) - Body ground - Ignition power supply (IG signal) Ignition switch ON → off 11 to 14 V → Below 1 V
      MB-30 (ACC) - Body ground - Ignition power supply (ACC signal) Ignition switch 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
      Driver seat belt unfastened Below 1 Ω
      MB-2 (RCTY) - Body ground* - Rear door courtesy light switch RH input Rear door RH closed (OFF) 10 kΩ or higher
      Rear door RH open (ON) Below 1 Ω
      MB-13 (LCTY) - Body ground* - Rear door courtesy light switch LH input Rear door LH closed (OFF) 10 kΩ or higher
      Rear door LH open (ON) Below 1 Ω

      • *: w/ Rear Seat Belt Warning

  2. CHECK COMBINATION METER ASSEMBLY

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    1. Disconnect the K21 combination meter assembly connector.

    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.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      K21-40 (B) - Body ground LA-B - Body ground Battery power supply Always 11 to 14 V
      K21-39 (IG+) - Body ground LA-GR - Body ground Ignition power supply (IG signal) Ignition switch ON → off 11 to 14 V → Below 1 V
      K21-21 (ES) - Body ground W- B - Body ground Ground Always Below 1 Ω
      K21-10 (PBKL) - Body ground*3 B*1, G*2 - Body ground Front passenger seat belt buckle switch signal Front passenger seat occupied, seat belt fastened 10 kΩ or higher
      Front passenger seat occupied, seat belt unfastened Below 1 Ω
      K21-11 (PODS) - Body ground*3 L - Body ground Occupant detection sensor signal Front passenger seat occupied Below 100 Ω
      Front passenger seat not occupied 1 MΩ or higher
      K21-24 (RLSB) - Body ground*4 SB - Body ground Rear LH seat belt buckle switch signal Rear LH seat belt fastened 10 kΩ or higher
      Rear LH seat belt unfastened Below 1 Ω
      K21-26 (RRSB) - Body ground*4 LG - Body ground Rear RH seat belt buckle switch signal Rear RH seat belt fastened 10 kΩ or higher
      Rear RH seat belt unfastened Below 1 Ω
      K21-25 (RCSB) - Body ground*4 B - Body ground Rear center seat belt buckle switch signal Rear center seat belt fastened 10 kΩ or higher
      Rear center seat belt unfastened Below 1 Ω

      • *1: for LHD

      • *2: for RHD

      • *3: w/ Front Passenger Seat Belt Warning System

      • *4: w/ Rear Seat Belt Warning

    3. Reconnect the K21 combination meter assembly connector.

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

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      K21-18 (RLMT) - Body ground* BE - Body ground Rear LH seat belt warning light output signal Ignition switch ON, rear seat belt warning light (LH) off 11 to 14 V
      Ignition switch ON, rear seat belt warning light (LH) on Below 1 V
      K21-19 (RCMT) - Body ground* R - Body ground Rear center seat belt warning light output signal Ignition switch ON, rear seat belt warning light (center) off 11 to 14 V
      Ignition switch ON, rear seat belt warning light (center) on Below 1 V
      K21-20 (RRMT) - Body ground* G - Body ground Rear RH seat belt warning light output signal Ignition switch ON, rear seat belt warning light (RH) off 11 to 14 V
      Ignition switch ON, rear seat belt warning light (RH) on Below 1 V

      • *: w/ Rear Seat Belt Warning