TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU

  1. CHECK TIRE PRESSURE WARNING ECU AND RECEIVER

    1. C250865C19

      *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.

      Tip:

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

      E129452C09

      *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. C240058C03

      *a

      Example

      *b

      GND

      Using an oscilloscope, check waveform 1.

      Table 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
      Tip:

      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.