TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU

CHECK TIRE PRESSURE WARNING ECU AND RECEIVER

1. 

   *A	w/ Rear Fog Light
   *B	w/o Rear Fog Light
   *a	Front view of wire harness connector (to Tire Pressure Warning ECU and Receiver)

   Disconnect the X45*1 or X78*2 tire pressure warning ECU and receiver connector and measure the voltage or resistance on the wire harness side.

   
   

   • *1: w/ Rear Fog Light

   • *2: w/o Rear Fog Light

   w/ Rear Fog Light

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   X45-1 (IG) - X45-12 (GND)	R - W-B	IG power source	Power switch on (IG)	10 to 16 V
   X45-7 (+B) - X45-12 (GND)	LG - W-B	Power supply (from auxiliary battery)	Always	10 to 16 V
   X45-9 (CANH) - X45-10 (CANL)	SB - P	CAN communication line	Power switch off	54 to 69 Ω
   X45-12 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω

   w/o Rear Fog Light

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   X78-1 (IG) - X78-12 (GND)	R - W-B	IG power source	Power switch on (IG)	10 to 16 V
   X78-9 (CANH) - X78-10 (CANL)	SB - P	CAN communication line	Power switch off	54 to 69 Ω
   X78-12 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω

2. Connect the X45*1 or X78*2 tire pressure warning ECU and receiver connector.

   
   

   • *1: w/ Rear Fog Light

   • *2: w/o Rear Fog Light

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.

   

   *A	w/ Rear Fog Light	*B	w/o Rear Fog Light
   *a	Component with harness connected (Tire Pressure Warning ECU and Receiver)	-	-

   w/ Rear Fog Light

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   X45-3 (CLSW) - X45-12 (GND)	W - W-B	Tire pressure warning reset switch	Power switch on (IG) Steering pad switch assembly operated, "Change tire pressure" selected on the multi-information display and "ENTER" switch (steering pad switch assembly) pressed and held	Below 1.5 V
   			Power switch on (IG) "ENTER" switch (steering pad switch assembly) off	8 to 15 V
   X45-4 (RDA) - X45-12 (GND)	GR - W-B	Output signals	Power switch on (IG)	Pulse generation (see waveform 1)
   X45-5 (PRG) - X45-12 (GND)	L - W-B	Input signals	Power switch on (IG)	Pulse generation (see waveform 1)

   w/o Rear Fog Light

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   X78-3 (CLSW) - X78-12 (GND)	W - W-B	Tire pressure warning reset switch	Power switch on (IG) Steering pad switch assembly operated, "Change tire pressure" selected on the multi-information display and "ENTER" switch (steering pad switch assembly) pressed and held	Below 1.5 V
   			Power switch on (IG) "ENTER" switch (steering pad switch assembly) off	8 to 15 V
   X78-4 (RDA2) - X78-12 (GND)	GR - W-B	Output signals	Power switch on (IG)	Pulse generation (see waveform 1)
   X78-5 (PRG2) - X78-12 (GND)	L - W-B	Input signals	Power switch on (IG)	Pulse generation (see waveform 1)

4. 

   *a	Example
   *b	GND

   Using an oscilloscope, check waveform 1.

   Waveform 1:

   Item	Contents
   Terminal	X45-4 (RDA) - X45-12 (GND)*1 X78-4 (RDA2) - X78-12 (GND)*2 X45-5 (PRG) - X45-12 (GND)*1 X78-5 (PRG2) - X78-12 (GND)*2
   Tool setting	5 V/DIV, 5 ms./DIV.
   Vehicle condition	Power switch on (IG)

   
   

   • *1: w/ Rear Fog Light

   • *2: w/o Rear Fog Light

   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.