B2124

Code

Other B — Body

Door Passenger Reset Switch Stuck Failure

Brand: Other

Type: B — Body

Views: UK: 24 EN: 35 RU: 23

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Page language: EN

Passenger door shows as continuously open or continuously closed on dash or scan tool
Interior lights or dome light behaving incorrectly when passenger door opened/closed
Central locking, auto-lock, or alarm may not operate correctly for passenger door
DTC B2124 stored and possibly repeated after clearing codes
Passenger door may not trigger chime or door-ajar warnings

Read freeze frame and live data with a diagnostic scan tool to observe switch state while opening/closing passenger door
Visually inspect passenger door latch area, switch body, and connector for damage, corrosion, or moisture
Operate door and observe BCM/scan-tool parameter to confirm whether the input changes state
Inspect the wiring harness through the door boot for pinched, frayed, or broken wires
Check for related codes (BCM, central locking, airbag/seatbelt sensors) that may indicate broader wiring issues

Expected: switch input changes state when door is opened vs closed (binary/pull-up or pull-down signal)
Typical idle values: near battery voltage (~12 V) when open or near 0 V when closed — verify against vehicle-specific data
No change or a constant voltage indicates stuck switch or wiring short/open
Intermittent or noisy signal may show fluctuating voltage or rapid state changes on live data

Connect a scan tool and confirm B2124 and any related freeze-frame/live-data. Note the reported state of the passenger door reset switch.
Visually inspect the passenger door switch or latch sensor and connector for contamination, corrosion, or damage. Dry and clean if contamination is present.
Operate the door while watching the scan-tool parameter. If the input never changes, proceed to wiring checks.
With the connector unplugged, check continuity/resistance of the switch (if removable) while actuating it. Compare to expected switch behavior (open/closed).
Backprobe the BCM or switch connector and measure voltage/ground reference while opening/closing the door to confirm signal transitions.
Inspect and flex the door wiring harness through the door boot to find intermittent breaks or shorts. Repair any damaged wiring or PINS.
If the switch is confirmed stuck or electrically open/shorted, replace the switch or latch assembly and retest.
If wiring and switch check good but input still stuck, inspect BCM connector and power/ground circuits. Consider BCM software update or module replacement only after ruling out wiring/switch.
After repairs, clear codes and perform multiple open/close cycles to confirm the fault does not return.