Body Control Module: Testing and Inspection

INSPECTION OF BCM AND IT'S 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 steering column hole cover from instrument panel.
3. 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" (Part 1):

BCM Connector "G31" (Part 2):

BCM Connector "G32":

Reference waveform No. 1
HVAC control module serial communication signal (1)









Reference waveform No. 2
HVAC control module and information display serial communication signal (1)









Reference waveform No. 3
Rear wiper LOW or INT signal (1)









Reference waveform No. 4
Illumination control output signal (1)









Reference waveform No. 5
SDM communication signal (1)









Reference waveform No. 6
Vehicle speed pulse output signal (1)









Reference waveform No. 7
CAN communication signal









Reference waveform No. 8
Brake fluid level, parking brake or driver side seat belt switch signal (1)









Reference waveform No. 9
Oil pressure switch signal (1)









Reference waveform No. 10
Keyless entry receiver signal (1)









Reference waveform No. 11
DRL control signal (1)









Reference waveform No. 12
Illumination control output signal (1)