B26A0

Code

Generic B — Body

Blind Spot Monitor Module Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 16 RU: 13

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Open/shorted or corroded wiring or connectors on the BSM module data, power or ground circuits
Blown fuse or loss of module supply voltage
Faulty BSM module
Gateway or CAN bus hardware fault (short, open, high resistance, termination issue)
Software/configuration mismatch or corrupted module software
Aftermarket devices or recent repairs that disturbed the vehicle network

Scan all modules and record all stored/active DTCs and freeze-frame data
Verify BSM module appears on the network via scan tool (module present/listed)
Visual inspection of BSM module connector(s), wiring harness and nearby connectors for damage, corrosion, water entry or rodent chewing
Check fuses, relay and measure module supply voltage and ground at the BSM connector with ignition on
Measure CAN bus idle voltages and continuity (see signal parameters)
Check for aftermarket devices or recent repairs that connected to the vehicle electrical system

CAN High (idle): ~2.5 V common-mode (varies slightly by vehicle); CAN Low (idle): ~2.5 V common-mode
CAN dominant state differential typically ~1.5–3.0 V (depends on transceiver and termination)
Common CAN bus speeds for BSM systems: 250 kb/s or 500 kb/s (verify on vehicle)
LIN or single-wire data (if used) ~0–12 V pulsed signaling (vehicle-specific)
Module supply: battery voltage (nominal 12 V) with ignition on; ground continuity to chassis

Use a capable scan tool to read and record DTCs from all modules and check for BSM module presence on the network.
If BSM module is not listed, verify power and ground at the BSM connector with key ON; check related fuses and fusible links.
Perform a visual/physical inspection of the BSM harness and connector for corrosion, water, damage or loose pins; repair as needed.
Check CAN bus using multimeter/oscilloscope: measure idle voltages on CAN_H and CAN_L, look for expected differential and clean waveforms; check for short to battery/ground.
If bus voltages/waveforms abnormal, isolate segments by disconnecting nearby modules (one at a time) to find the faulty device or shorted harness section.
Check connector pin resistance/continuity between BSM connector and gateway/junction; repair open or high resistance circuits.
If wiring and bus are good, check for software updates or reprogramming for the BSM/gateway; reflash if manufacturer recommends.
Replace BSM module only after confirming correct power, grounds and bus integrity and if module fails bench or vehicle communication tests.
Clear DTCs and perform a functional test and road test; monitor for return of the code and verify system operation.

CAN/LIN bus wiring fault between BSM and gateway (broken wire, short to battery or ground, poor connector pin contact)
Loss of BSM module battery power or ground (fuse, fusible link, poor ground)
Faulty BSM module (internal failure)
Network gateway or other module interfering with bus communications
Software/firmware issue or module requiring reprogramming