TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU


  1. CHECK TIRE PRESSURE WARNING ECU AND RECEIVER


    1. A012FI5C19
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      Disconnect the L70 tire pressure warning ECU and receiver connector and measure the voltage and resistance on the wire harness side.

      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      L70-1 (IG) - L70-12 (GND) SB - BR IG power source Ignition switch ON 10 to 16 V
      L70-7 (+B)* - L70-12 (GND) P - BR Power supply (from battery) Always 10 to 16 V
      L70-12 (GND) - Body ground BR - Body ground Ground Always Below 1 Ω

      *: w/o Entry and Start System

    2. Connect the L70 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.

      A012HKKC09
      *a

      Component with harness connected

      (Tire Pressure Warning ECU and Receiver)

      		 - -
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      L70-3 (CLSW) - L70-12 (GND) B - BR Tire pressure warning reset switch

      • Ignition switch ON

      • Tire pressure warning reset switch on

      		 Below 1.5 V

      • Ignition switch ON

      • Tire pressure warning reset switch off

      		 8 to 15 V
      L70-4 (RDA2) - L70-12 (GND) G - BR Output signals Ignition switch ON Pulse generation (see waveform 1)
      L70-5 (PRG2) - L70-12 (GND) Y - BR Input signals Ignition switch ON Pulse generation (see waveform 1)
      L70-9 (PRG3)* - L70-12 (GND) P - BR Output signals Ignition switch ON → Ignition switch off 0 V → 16 V
      L70-10 (RDA3)* - L70-12 (GND) GR - BR Input signals Ignition switch ON → Ignition switch off 0 V → 16 V

      *: w/o Entry and Start System

    4. A012IRFC03
      *a Example
      *b GND

      Using an oscilloscope, check waveform 1.

      Waveform 1:
      Item Contents
      Terminal

      L70-4 (RDA2) - L70-12 (GND)

      L70-5 (PRG2) - L70-12 (GND)
      Tool setting 5 V/DIV, 5 ms./DIV.
      Vehicle condition Ignition switch ON

      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.