B0146

Code

Generic B — Body

Body Control Module: Driver Door Lock Switch Circuit Fault

Brand: Generic

Type: B — Body

Views: UK: 19 EN: 21 RU: 16

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Page language: EN

Read BCM codes and freeze-frame/monitor data with a scanner; note related codes
Visually inspect driver door switch, connector, and door harness for damage or water
Wiggle test the harness while observing lock operation or live data
Backprobe the switch connector and measure signal with switch actuated and released
Measure reference voltage and ground at the switch connector
Check continuity between switch signal pin and BCM input pin (with power off)

Reference voltage: typically 5 V or 12 V depending on vehicle — confirm with wiring diagram
Switch closed: signal typically pulled to ground (near 0 V) or to battery voltage (~9–14 V) depending on design
Switch open: signal should float to pull-up level (approx. reference voltage) or show high impedance
Expected closed switch resistance: low (a few ohms to tens of ohms) across switch contacts
No-load current: very low; large current indicates short to ground or power

Connect a scan tool, record DTCs and live data for the driver door lock switch input. Note freeze-frame conditions.
Verify symptom: operate the driver door lock switch while observing the scanner or multimeter. Confirm whether the BCM sees state changes.
Visually inspect switch, connector, and wiring for damage, corrosion, or water ingress. Repair as needed.
Backprobe the switch connector. With ignition ON, measure reference voltage, signal voltage with switch pressed and released, and ground continuity.
If signal does not change or shows abnormal voltage, disconnect the switch. Check continuity and resistance between the switch signal pin and the BCM input pin (power OFF).
Check for shorts: measure resistance from the signal wire to battery positive and to chassis ground. Infinite/very high = no short; low resistance indicates short.
If wiring and connector are good, substitute a known-good switch or bench-test the switch for internal faults. Replace switch if faulty.
If the switch and wiring pass tests but the input at the BCM is still abnormal, inspect BCM connector pins for damage and re-test. Consider BCM software/configuration or module fault.
After repairs, clear codes and retest all door lock functions; confirm code does not return and freeze-frame conditions resolved.
If code persists after verifying wiring and switch, consult vehicle-specific wiring diagrams and consider BCM repair or replacement as a last step.