B29D4

Code

Generic B — Body

Blind Spot Monitoring Sensor Circuit - Right Rear

Brand: Generic

Type: B — Body

Views: UK: 11 EN: 17 RU: 16

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or shorted wiring between right rear BSM sensor and control module
Poor or corroded connector pins at the sensor or module
Broken ground or high-resistance ground at sensor
Low or missing supply voltage (fuse, power distribution, relay)
Sensor hardware failure (radar/ultrasonic module)
Intermittent connection due to water ingress, damage, or poor repair

Symptoms

Blind spot warning for right rear inoperative or disabled
False or missing blind spot alerts on the right side
BSM warning lamp or message displayed on dash
Related systems (lane change assist, cross-traffic alert) may be degraded for right side
DTC present and may be accompanied by other communication codes

What to check

Use a scan tool to read BSM live data, freeze-frame and any related codes
Visually inspect right rear sensor, bracket and mounting for damage, contamination or misalignment
Inspect sensor connector for corrosion, bent pins, moisture, and locking tab condition
Check fuses and relays powering the BSM module and sensors
Wiggle harness while monitoring live data or MIL to reproduce intermittent faults
Verify vehicle service bulletins for BSM faults and required calibrations

Signal parameters

Sensor supply voltage: nominal vehicle battery ~11–14 V at the sensor power pin when ignition on
Ground: near 0 Ω continuity to chassis ground (low resistance)
Communication: CAN bus idle voltages ~2.5 V on CAN High/Low; loss of CAN messages indicates comms fault
Module/sensor diagnostics: sensor should report presence and self-test status via scan tool
Typical analog/digital signal levels vary by manufacturer—reference OEM pinout and wiring diagram for exact values

Diagnostic algorithm

Connect a capable scan tool, record the code, time stamp and any related U-codes; view live data for the right rear sensor and attempt sensor self-test.
Visually inspect right rear sensor and harness for damage, moisture, or corrosion; repair physical damage before electrical tests.
With ignition ON, back-probe the sensor connector: verify battery feed voltage (~11–14 V) and good ground continuity. If no power, trace to fuse/relay and power distribution.
Back-probe communication lines (CAN/LIN) and verify proper idle voltages (~2.5 V); check for lost or corrupted messages using a scan tool or oscilloscope.
Perform a wiggle test on wiring and connector while watching live data for intermittent drops; repair chafing or broken conductors found.
If wiring and power/ground/comm are good, unplug and inspect pins for corrosion; clean or replace connector as needed.
Swap with a known-good right rear sensor (if available) or substitute a bench-tested module to confirm sensor vs harness/module fault.
If sensor replacement is required, install new sensor and follow OEM calibration/relearn procedures for blind spot system.
Clear codes and retest vehicle operation and live data; road test to confirm remedy and that no secondary codes return.
If the fault persists after sensor and harness repair, investigate the BSM control module and related CAN gateway for internal faults and reference OEM repair information.

Likely causes

Wiring/connectors damaged or corroded at right rear sensor
Failed right rear BSM sensor module
Poor ground or blown/loose fuse feeding the sensor module
Intermittent harness contact from water ingress or body damage

Fault status

⚠️ Status

Stored when the right rear blind spot sensor reports an electrical or communication fault; may be logged as current, intermittent, or pending depending on conditions and OEM logic.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours