B29C3

Code

Generic B — Body

Right rear radar sensor communication fault

Brand: Generic

Type: B — Body

Views: UK: 13 EN: 14 RU: 15

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or corroded sensor connector or wiring harness (open, short, high resistance)
Failed right rear radar sensor (internal electronics)
Intermittent or lost power or ground to the sensor (blown fuse, poor ground)
CAN/LIN bus fault (open, short to battery/ground, missing termination, high bus error rate)
Software/configuration mismatch or module calibration issue
Physical damage or water ingress to sensor

Symptoms

ADAS warnings illuminated (e.g., radar sensor fault, lane/parking assist disabled)
Right rear radar listed as unavailable or offline in scan tool
Loss of blind spot detection, rear cross-traffic alert, or parking assist related to that corner
Intermittent or no object detection on right rear side
Possible multiple related communication DTCs present

What to check

Retrieve and record all DTCs from ADAS, radar sensor module (if present), and gateway; note freeze-frame/live-data
Visually inspect the right rear radar sensor and connector for corrosion, bent pins, moisture, or physical damage
Check for other modules reporting lost communication with the same sensor
With ignition ON, measure sensor supply voltage and ground at the sensor connector (compare to vehicle battery and spec)
Use a scan tool to monitor the radar sensor CAN/LIN message stream and module status; note message IDs and update rates
Perform wiggle test on harness while monitoring live data or bus errors to reproduce fault

Signal parameters

Typical bus: CAN (module-specific CAN ID) — check vehicle service info for exact ID
Message update rate: commonly 5–50 Hz (module dependent)
Payload fields: sensor status/health, object count, range, azimuth, relative velocity, confidence/quality, internal temperature
Diagnostic frames: module alive/heartbeat, diagnostics and fault/status bits
Error protection: CRC/checksum or counter fields present in message

Diagnostic algorithm

Read and record all related DTCs and freeze-frame data from ADAS and body/control modules. Note any additional network DTCs (U-codes).
Check wiring and connector: visually inspect the right rear radar sensor connector for corrosion, bent pins, and water. Disconnect and inspect mating surfaces. Repair or clean as needed.
Verify power and ground at the sensor connector with ignition ON. Compare measured voltages to specification (vehicle service data). Repair power/ground faults or blown fuses.
Using a scan tool, verify the sensor’s CAN/LIN messages (alive/heartbeat). Note CAN ID and update rate. If no messages, proceed to wiring/can bus checks.
Check CAN bus physical layer: measure CANH/CANL voltages at the sensor connector, observe idle voltages, and use oscilloscope to check for noise, missing differential signal, or bus errors. Verify termination resistances.
Wiggle harness while monitoring bus and DTCs to try to reproduce the fault; repair intermittent wiring faults found.
If wiring and bus integrity are confirmed, perform sensor self-test or diagnostics per manufacturer procedure. Reprogram or update sensor/module software if a known firmware issue exists.
If sensor fails internal tests and wiring/bus are good, replace the right rear radar sensor and clear codes. Re-run diagnostics and perform any required sensor/module calibrations.
After repair or replacement, verify system functions and perform road test and ADAS self-checks to confirm communication and operation.
If problem persists after replacing sensor and repairing wiring, inspect ADAS/main control module or gateway for internal faults or require module reflash/replace.

Likely causes

Connector/wiring damage or corrosion causing intermittent or no communication
Right rear radar sensor internal failure
Loss of sensor supply voltage or bad ground
CAN bus wiring problem or missing termination

Fault status

⚠️ Status

Right rear radar sensor communication fault — the ADAS/controller is not receiving valid messages from the right rear radar sensor (lost, corrupted, or invalid communication).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours