Terminals Of Ecu

HINT:

Inspect the connectors from the back side.

1. CHECK TIRE PRESSURE WARNING ECU 
   Fig 1: Identifying Tire Pressure Warning ECU Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   VOLTAGE AND RESISTANCE SPECIFICATION
   
   

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   D78-2 (SPD) - D78-9 (GND)	V - W-B	Vehicle speed signal	Vehicle is running	Pulse generation (see  awaveform 1)
   D78-3 (TC) - D78-9 (GND)	G - W-B	TC terminal	When terminal TC is not connected	11 to 14 V
   D78-4 (TACH) - D78-9 (GND)	R - W-B	Engine speed signal	Engine is running	Pulse generation (see  bwaveform 2)
   D78-5 (IND) - D78-9 (GND)	O - W-B	Tire pressure warning light output signal	After ignition switch is turned ON, when tire pressure warning light illuminates for 3 seconds	1.6 to 2.4 V
   			Ignition switch ON	Tire pressure warning light off 4.0 V or higher
   D78-6 (RF5V) - D78-9 (GND)	W - W-B	Tire pressure warning antenna and receiver power source	Ignition switch ON	4.5 to 5.5 V
   D78-7 (IG) - D78-9 (GND)	R - W-B	IG power source	Ignition switch ON	11 to 14 V
   D78-9 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω
   D78-10 (SIL) - D78-9 (GND)	W - W-B	Diagnosis tester communication line	Ignition switch ON, when communication is not performed with a tester	11 to 14 V
   D78-11 (GND2) - D78-9 (GND)	GR - W-B	Tire pressure warning antenna and receiver ground	Always	Below 1
   D78-12 (RDA) - D78-9 (GND)	B - W-B	Tire pressure warning antenna and receiver signal	Ignition switch ON	Below 2 V

   1. Using an oscilloscope, check the waveform 1.
      WAVEFORM 1 REFERENCE
      
      

      Item	Contents
      Terminal No. (Symbols)	D78-2 (SPD) - D78-9 (GND)
      Tool Setting	5V/DIV., 200 ms/DIV.
      Vehicle Condition	While driving at approximately 20 km/h (12 mph).

      Fig 2: Waveform 1 Graph

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      The wavelength becomes shorter as the vehicle speed increases.

   2. Using an oscilloscope, check the waveform 2.
      WAVEFORM 2 REFERENCE
      
      

      Item	Contents
      Terminal No. (Symbols)	D78-4 (TACH) - D78-9 (GND)
      Tool Setting	5V/DIV., 10 ms/DIV.
      Vehicle Condition	Idling

      Fig 3: Waveform 2 Graph

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      The wavelength becomes shorter as the engine speed increases.