INSPECTION PROCEDURE USING AN OSCILLOSCOPE



MAIN BATTERY GROUND FAULT DETECTOR

<Measurement Method>

1.Connect each oscilloscope channel probe with the terminal No. 35 (main battery ground fault detector) and terminal No. 46 (main battery ground fault detector pre-check signal) of the BMU connector.

<Standard Wave Pattern>



Observation condition
Function
 Special patterns
Pattern height
 Low
Pattern selector
 Display
Electric motor switch
 "LOCK" (OFF) → ON


<Description of Wave Patterns>



  • The BMU sends the pre-check signal to the main battery ground fault detector to check whether the main battery ground fault detector correctly operates.
  • When receiving the pre-check signal, the main battery ground fault detector should output the high signal to the BMU.

<Wave Pattern Observation Points>



  • Check that the wave pattern of the main battery ground fault detector pre-check signal and that of the main battery ground fault detector output are the same.

<Examples of Abnormal Wave Patterns>

Example 1
Wave pattern characteristics
  • The wave pattern of the pre-check signal is not output during the pre-check of the main battery ground fault detector.
Cause of problem
  • Failed main battery ground fault detector circuit
  • Failed BMU

Example 2
Wave pattern characteristics
  • Although the wave pattern of the main battery ground fault detector pre-check signal is output, the wave pattern is not output from the main battery ground fault detector.
Cause of problem
  • Failed main battery ground fault detector circuit
  • Malfunction of sensor interface

Example 3
Wave pattern characteristics
  • The high signal is output from the main battery ground fault detector even except the pre-check of the main battery ground fault detector.
Cause of problem
  • Failed main battery ground fault detector circuit
  • Ground fault of high voltage system components

MAIN BATTERY COOLING FAN

<Measurement Method>

1.Disconnect the main battery cooling fan intermediate connector, and then connect the special tool test harness (MB991658) in between. (Always mate all the terminals.)
2.Connect the oscilloscope probe to terminal No. 2 of main battery cooling fan intermediate connector.
note If using the BMU connector to perform the measurement, connect each channel probe of the oscilloscope with the terminal No.13.

<Standard wave pattern>



Observation condition
Function
 Special patterns
Pattern height
 Low
Pattern selector
 Display
Electric motor switch
  • "LOCK" (OFF)
  • Right after charging cable is connected (while driving main battery cooling fan)


<Description of Wave Patterns>
  • The BMU sends the duty signal to the main battery cooling fan to drive the main battery cooling fan.

<Wave Pattern Observation Points>

  • While the main battery cooling fan is rotated, approximately 10 % duty signal should be output.

<Examples of Abnormal Wave Pattern
Example 1
Wave pattern characteristics
  • The main battery cooling fan PWM signal is always the high signal or the low signal.
Cause of problem
  • Failed main battery cooling fan circuit