TIRE PRESSURE WARNING SYSTEM TERMINALS OF ECU

CHECK TIRE PRESSURE WARNING ECU AND RECEIVER

1. Measure the voltage and resistance according to the value(s) in the table below. If the result is not as specified, the ECU may have a malfunction.

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   K39-1 (IG) - K39-12 (GND)	L - W-B	IG power source	Ignition switch ON (IG)	11 to 14 V
   K39-3 (CLSW) - K39-12 (GND)	LG - W-B	Tire pressure warning reset switch	Ignition switch ON (IG) Tire pressure warning reset switch on	Below 1.5 V
   			Ignition switch ON (IG) Tire pressure warning reset switch off	8 to 14 V
   K39-4 (RDA2) - K39-12 (GND)	P - W-B	Output signals	Ignition switch ON (IG)	Pulse generation (see waveform 1)
   K39-5 (PRG2) - K39-12 (GND)	GR - W-B	Input signals	Ignition switch ON (IG)	Pulse generation (see waveform 1)
   K39-7 (+B) - K39-12 (GND) *1, *2	R - W-B	Auxiliary battery	Ignition switch off	11 to 14 V
   K39-12 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω

   
   

   • *1: w/o Power Switch

   • *2: w/ Wireless Door Lock System

2. 

   Text in Illustration

   *a	Example
   *b	GND

   Using an oscilloscope, check waveform 1.

   Waveform 1:

   Item	Contents
   Terminal	K39-4 (RDA2) - K39-12 (GND) K39-5 (PRG2) - K39-12 (GND)
   Tool setting	5 V/DIV., 500 μs./DIV.
   Vehicle condition	Ignition switch ON (IG)

   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.