TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU


  1. CHECK TIRE PRESSURE WARNING ECU AND RECEIVER


    1. A019KHCE13
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      Disconnect the P48 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
      P48-1 (IG) - P48-12 (GND) V - W-B IG power source Engine switch on (IG) 10 to 16 V
      P48-9 (GND3) - Body ground - Tire pressure warning system presence judgment ground Always Below 1 Ω
      P48-12 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω

    2. Connect the P48 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

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

      A019N0JE68
      Text in Illustration
      *a

      Component with harness connected

      (Tire Pressure Warning ECU and Receiver)

      		 - -
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      P48-2 (SPD) - P48-12 (GND) L - W-B Vehicle speed signal Vehicle is running Pulse generation (see waveform 1)
      P48-3 (TC) - P48-12 (GND) G - W-B TC terminal Terminal TC is not connected 11 to 14 V
      P48-5 (IND) - P48-12 (GND) P - W-B Tire pressure warning light output signal

      • Engine switch on (IG)

      • Tire pressure warning light off

      		 3.2 V or higher

      • Engine switch on (IG)

      • Tire pressure warning light on

      		 0.9 to 3.2 V
      P48-7 (CLSW) - P48-12 (GND) GR - W-B Tire pressure warning reset switch signal

      • Engine switch on (IG)

      • Tire pressure warning reset switch on

      		 Below 2.4 V

      • Engine switch on (IG)

      • Tire pressure warning reset switch off

      		 8 to 15 V
      P48-10 (SIL) - P48-12 (GND) BE - W-B Diagnostic tester communication line Engine switch on (IG) 11 to 14 V
    4. A019MDTE40
      Text in Illustration
      *a GND

      Using an oscilloscope, check waveform 1.

      Waveform 1:
      Item Contents
      Terminal P48-2 (SPD) - P48-12 (GND)
      Tool setting 5 V/DIV., 20 ms./DIV.
      Vehicle condition Driving at 20 km/h (12 mph)

      Tech Tips

      The wavelength becomes shorter as the vehicle speed increases.