TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU


  1. CHECK TIRE PRESSURE WARNING ECU AND RECEIVER


    1. A01G52JE06
      Text in Illustration
      *A for FMVSS138 Type
      *B for ECE-R64 Type
      *a

      Front view of wire harness connector

      (to Tire Pressure Warning ECU and Receiver)

      Disconnect the P29 or P25 tire pressure warning ECU and receiver connector and measure the voltage or resistance on the wire harness side.

      for FMVSS138 Type
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      P29-1 (IG) - P29-12 (GND) GR - W-B IG power source Engine switch on (IG) 10 to 16 V
      P29-7 (+B) - P29-12 (GND) W - W-B Power supply (from battery) Always 10 to 16 V
      P29-12 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω
      for ECE-R64 Type
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      P25-1 (IG) - P25-12 (GND) GR - W-B IG power source Engine switch on (IG) 10 to 16 V
      P25-12 (GND) - Body ground W-B - Body ground Ground Always Below 1 Ω

    2. Connect the P29 or P25 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.

      A01G4IQE61
      Text in Illustration
      *A for FMVSS138 Type *B for ECE-R64 Type
      *a

      Component with harness connected

      (Tire Pressure Warning ECU and Receiver)

      		 - -
      for FMVSS138 Type
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      P29-3 (CLSW) - P29-12 (GND) R - 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
      P29-4 (RDA) - P29-12 (GND) W - W-B Output signals Engine switch on (IG) Pulse generation (see waveform 1)
      P29-5 (PRG) - P29-12 (GND) P - W-B Input signals Engine switch on (IG) Pulse generation (see waveform 1)
      P29-8 (ALSI) - P29-12 (GND) LG - W-B Tire pressure monitor initiator driver Engine switch on (IG) Pulse generation (see waveform 1)
      for ECE-R64 Type
      Terminal No. (Symbol) Wiring Color Terminal Description Condition Specified Condition
      P25-3 (CLSW) - P25-12 (GND) R - 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
      P25-4 (RDA2) - P25-12 (GND) W - W-B Output signals Engine switch on (IG) Pulse generation (see waveform 1)
      P25-5 (PRG2) - P25-12 (GND) P - W-B Input signals Engine switch on (IG) Pulse generation (see waveform 1)
      P25-8 (ALSI) - P25-12 (GND) LG - W-B Tire pressure monitor initiator driver Engine switch on (IG) Pulse generation (see waveform 1)
    4. A01G4TKE01
      Text in Illustration
      *a Example
      *b GND

      Using an oscilloscope, check waveform 1.

      Waveform 1:
      Item Contents
      Terminal

      P29-4 (RDA) - P29-12 (GND)*1

      P29-5 (PRG) - P29-12 (GND)*1

      P29-8 (ALSI) - P29-12 (GND)*1

      P25-4 (RDA2) - P25-12 (GND)*2

      P25-5 (PRG2) - P25-12 (GND)*2

      P25-8 (ALSI) - P25-12 (GND)*2
      Tool setting 5 V/DIV, 5 ms./DIV.
      Vehicle condition Engine switch on (IG)

      • *1: for FMVSS138 Type

      • *2: for ECE-R64 Type

      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.