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.

CAUTION: BCM cannot be checked by itself. It is strictly prohibited to connect voltmeter or ohmmeter to BCM with couplers disconnected from it.

Voltage Check
1. Disconnect negative cable (-) at battery.
2. Remove BCM.
3. Connect connectors to BCM.
4. Check voltage at each terminal number of couplers connected. For connector and terminal number, refer to 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 "G30"






BCM connector "G31"









BCM connector "G32"






Reference waveform No. 1
Rear wiper signal (1)

Reference Waveform No. 1:

Reference waveform No. 2
Illumination control output signal (1)

Reference Waveform No. 2:

Reference waveform No. 3
SDM communication signal (1)

Reference Waveform No. 3:

Reference waveform No. 4
Auto-on headlight, brake fluid level, parking brake or driver side seat belt switch signal (1)

Reference Waveform No. 4:

Reference waveform No. 5
Vehicle speed pulse output signal (1)

Reference Waveform No. 5:

Reference waveform No. 6
CAN communication signal

Reference Waveform No. 6:

Reference waveform No. 7
Oil pressure switch signal (1)

Reference Waveform No. 7:

Reference waveform No. 8
Keyless entry receiver signal

Reference Waveform No. 8:

Reference waveform No. 9
DRL control signal (1)

Reference Waveform No. 9:

Reference waveform No. 10
Illumination control output signal (1)

Reference Waveform No. 10: