TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU


  1. CHECK TIRE PRESSURE WARNING ECU AND RECEIVER


    1. Disconnect the tire pressure warning ECU and receiver L175 connector and measure the voltage and resistance on the wire harness side.

      A01GX56E04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      - -
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      L175-1 (IG) - L175-4 (GND) V - W-B IG power source Power switch on (IG) 10 to 16 V
      L175-4 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω
    2. Connect the tire pressure warning ECU and receiver L175 connector.

    3. Measure the voltage according to the value(s) in the table below. If the result is not as specified, the ECU may have a malfunction.

      Tech Tips

      Inspect the connectors from the back side while the connectors are connected.

      A01H111E04
      Text in Illustration
      *a

      Component with harness connected

      (Tire Pressure Warning ECU and Receiver)

      - -
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      L175-2 (CLSW) - L175-4 (GND) P - W-B Tire pressure warning reset switch
      • Power switch on (IG)

      • Tire pressure warning reset switch ON

      Below 2.4 V

      • Power switch on (IG)

      • Tire pressure warning reset switch OFF

      8 to 15 V
      L175-5 (ALSI) - L175-4 (GND) L - W-B Tire pressure monitor initiator driver Power switch on (IG) Pulse generation (see waveform 1)
    4. A01H216E01
      Text in Illustration
      *a Example
      *b GND

      Using an oscilloscope, check waveform 1.

      Waveform 1:
      Item Contents
      Terminal L175-5 (ALSI) - L175-4 (GND)
      Tool setting 5 V/DIV, 5 ms./DIV.
      Vehicle condition Power switch on (IG)

      Tech Tips

      The waveform shown in the illustration is an example. If the tester displays a waveform that alternates between high and low, where high is a voltage that is between the IG power source voltage and a voltage 2.2 V lower than the IG power source voltage, and where low is a voltage of between 0 and 1.2 V, the ECU can be judged normal.