TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU

CHECK TIRE PRESSURE WARNING ECU AND RECEIVER

1. 

   *A	for Tire Pressure Warning ECU and Receiver Integrated with Electrical Key Receiver
   *B	for Tire Pressure Warning ECU and Receiver (Stand Alone)
   *a	Front view of wire harness connector (to Tire Pressure Warning ECU and Receiver)

   Disconnect the U33 or U32 tire pressure warning ECU and receiver connector and measure the voltage or resistance on the wire harness side.

   for Tire Pressure Warning ECU and Receiver Integrated with Electrical Key Receiver

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   U33-1 (IG) - U33-12 (GND)	B - BR	IG power source	Engine switch on (IG)	10 to 16 V
   U33-7 (+B) - U33-12 (GND)	G - BR	Power supply (from battery)	Always	10 to 16 V
   U33-12 (GND) - Body ground	BR - Body ground	Ground	Always	Below 1 Ω

   for Tire Pressure Warning ECU and Receiver (Stand Alone)

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   U32-1 (IG) - U32-12 (GND)	Y - BR	IG power source	Engine switch on (IG)	10 to 16 V
   U32-12 (GND) - Body ground	BR - Body ground	Ground	Always	Below 1 Ω

2. Connect the U33 or U32 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.

   

   *A	for Tire Pressure Warning ECU and Receiver Integrated with Electrical Key Receiver	*B	for Tire Pressure Warning ECU and Receiver (Stand Alone)
   *a	Component with harness connected (Tire Pressure Warning ECU and Receiver)	-	-

   for Tire Pressure Warning ECU and Receiver Integrated with Electrical Key Receiver

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   U33-3 (CLSW) - U33-12 (GND)	W - BR	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
   U33-4 (RDA) - U33-12 (GND)	G - BR	Output signals	Engine switch on (IG)	Pulse generation (see waveform 1)
   U33-5 (PRG) - U33-12 (GND)	L - BR	Input signals	Engine switch on (IG)	Pulse generation (see waveform 1)
   U33-8 (ALSI)* - U33-12 (GND)	R - BR	Tire pressure monitor initiator driver	Engine switch on (IG)	Pulse generation (see waveform 1)

   *: w/ Tire Inflation Pressure Display Function

   for Tire Pressure Warning ECU and Receiver (Stand Alone)

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   U32-3 (CLSW) - U32-12 (GND)	W - BR	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
   U32-4 (RDA2) - U32-12 (GND)	G - BR	Output signals	Engine switch on (IG)	Pulse generation (see waveform 1)
   U32-5 (PRG2) - U32-12 (GND)	L - BR	Input signals	Engine switch on (IG)	Pulse generation (see waveform 1)

4. 

   *a	Example
   *b	GND

   Using an oscilloscope, check waveform 1.

   Waveform 1:

   Item	Contents
   Terminal	U33-4 (RDA) - U33-12 (GND)*1 U33-5 (PRG) - U33-12 (GND)*1 U33-8 (ALSI) - U33-12 (GND)*1 U32-4 (RDA2) - U32-12 (GND)*2 U32-5 (PRG2) - U32-12 (GND)*2
   Tool setting	5 V/DIV, 5 ms./DIV.
   Vehicle condition	Engine switch on (IG)

   
   

   • *1: for Tire Pressure Warning ECU and Receiver Integrated with Electrical Key Receiver

   • *2: for Tire Pressure Warning ECU and Receiver (Stand Alone)

   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.