TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU


  1. CHECK TIRE PRESSURE WARNING ECU AND RECEIVER


    1. A0028QDC10
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      Disconnect the M45 tire pressure warning ECU and receiver connector and measure the voltage or resistance on the wire harness side.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      M45-1 (IG) - M45-12 (GND) Y - W-B IG power source Engine switch on (IG) 10 to 16 V
      M45-7 (+B) - M45-12 (GND) V - W-B Power supply (from battery) Always 10 to 16 V
      M45-12 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω

    2. Connect the M45 tire pressure warning ECU and receiver connector.

    3. Measure the voltage and resistance according to the value(s) in the table below. If the result is not as specified, the ECU may be malfunctioning.

      Tech Tips

      Measure the values on the wire harness side while the connector is connected.

      A0026U3C51
      *a

      Component without harness connected

      (Tire Pressure Warning ECU and Receiver)

      		 - -
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      M45-3 (CLSW) - M45-12 (GND) BE - W-B Tire pressure warning reset switch

      • Engine switch on (IG)

      • Tire pressure warning reset switch on

      		 Below 1.5 V

      • Engine switch on (IG)

      • Tire pressure warning reset switch off

      		 8 to 15 V
      M45-4 (RDA) - M45-12 (GND) LG - W-B Output signals Engine switch on (IG) Pulse generation (see waveform 1)
      M45-5 (PRG) - M45-12 (GND) SB - W-B Input signals Engine switch on (IG) Pulse generation (see waveform 1)
    4. A00283GC03
      *a Example
      *b GND

      Using an oscilloscope, check waveform 1.

      Waveform 1:
      Item Contents
      Terminal

      M45-4 (RDA) -M45-12 (GND)

      M45-5 (PRG) - M45-12 (GND)
      Tool setting 5 V/DIV, 5 ms./DIV.
      Vehicle condition Engine 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.