Inspection of BCM and Its Circuits

Inspection of BCM and Its Circuits

BCM and its circuits can be checked at BCM wiring couplers by measuring voltage and resistance.

NOTE:

If you connect a voltmeter or ohmmeter directly to the BCM by disconnecting the BCM connectors, you can damage the BCM.

Never connect a voltmeter or an ohmmeter directly to any terminal on the BCM by disconnecting the BCM connectors.

Voltage Check

1) Remove BCM referring to Service and Repair BCM Removal and Installation.
2) Connect connectors to BCM (1).
3) Check voltage at each terminal number of couplers connected.

For connector and terminal number, refer to [1][2]Body Control Module Connector Layout Diagram of BCM.






NOTE:

- As each terminal voltage is affected by the battery voltage, confirm that it is 11 V or more when ignition switch is ON.
- Voltage with asterisk (*) can not be measured by voltmeter because it is pulse signal.
Check it with oscilloscope if necessary.

BCM connector "G04"











BCM connector "G05"















BCM connector "G06"







Reference Waveform

NOTE:

- Waveform analysis is as follows.











- Waveform might change for measurement condition and vehicle spec.

Reference waveform No. 1

HVAC control module serial communication signal (1)











Reference waveform No. 2

Rear wiper ON or INT signal (1)











Reference waveform No. 3

SDM communication signal (1)











Reference waveform No. 4

A/C or rear end door window / back window defogger switch signal (1)











Reference waveform No. 5

Vehicle speed pulse output signal (1)











Reference waveform No. 6

CAN communication signal
















Reference waveform No. 7

Brake fluid level, parking brake or driver side seat belt switch signal (1)











Reference waveform No. 8

Oil pressure switch signal (1)











Reference waveform No. 9

Keyless entry receiver signal (1)











Reference waveform No. 10

DRL control signal (1)