CHARGING SYSTEM TERMINALS OF ECU

Using an oscilloscope, check the signal waveform of the ECU.

1. 

   Waveform 1

   Tech Tips

   As the duty cycle changes in accordance with the electrical load and battery condition, the output waveform also changes.

   

   Waveform 2

   Tech Tips

   As the duty cycle changes in accordance with the electrical load and battery condition, the output waveform also changes.

   

   Waveform 3

   Tech Tips

   As the duty cycle changes in accordance with the electrical load and battery condition, the output waveform also changes.

   CHECK POWER MANAGEMENT CONTROL ECU (w/o Entry and Start System)

   

   
   

   1. Measure the voltage and resistance according to the value(s) in the table below.

      Tech Tips

      Perform the measurements with the connectors connected.

   Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
   H72-8 (AM21) - Body ground	B - Body ground	Battery	Always	9.5 to 16 V
   H72-12 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω
   H73-14 (RLO) - H73-18 (E2)	V - BR	Generator signal	Engine warmed up, charging control operating, vehicle driven at constant speed	Pulse generation (See waveform 1)
   			Engine warmed up, charging control operating, vehicle accelerating	Pulse generation (See waveform 2)
   			Engine warmed up, charging control operating, vehicle decelerating	Pulse generation (See waveform 3)
   H73-12 (VC) - H73-18 (E2)	W - BR	Battery current sensor power supply	Ignition switch ON	4.5 to 5.5 V
   H73-15 (THB) - H73-18 (E2)	P - BR	Battery current sensor thermistor signal	Ignition switch ON (Temperature of thermistor of battery current sensor: -30 to 90°C (-22 to 194°F))	0.5 to 4.5 V
   H73-13 (IB) - H73-18 (E2)	B - BR	Battery current sensor signal	Ignition switch ON (Temperature of thermistor of battery current sensor: -30 to 90°C (-22 to 194°F))	0.5 to 4.5 V
   H73-18 (E2) - Body ground	BR - Body ground	Battery current sensor ground	Always	Below 1 Ω

   If the result is not as specified, the ECU may have a malfunction.

2. Using an oscilloscope, check the signal waveform of the ECU.

   Tech Tips

   The oscilloscope waveform shown in the illustration is an example for reference only. Waveforms with noise or chattering are not shown.

   
   

   1. 

      Waveform 1

      Tech Tips

      As the duty cycle changes in accordance with the electrical load and battery condition, the output waveform also changes.

      

      Waveform 2

      Tech Tips

      As the duty cycle changes in accordance with the electrical load and battery condition, the output waveform also changes.

      

      Waveform 3

      Tech Tips

      As the duty cycle changes in accordance with the electrical load and battery condition, the output waveform also changes.