U023E

Code

Generic U — Network/User

Lost Communication With Front Distance Range Sensor - Right

Brand: Generic

Type: U — Network/User

Views: UK: 28 EN: 31 RU: 26

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Page language: EN

Causes

Damaged or disconnected sensor connector
Corroded or bent pins in the sensor or harness connector
Broken, shorted or chafed wiring between sensor and main module/CAN bus
No power or poor ground to the sensor (blown fuse, open circuit)
CAN bus wiring fault (short to ground/battery, missing termination)
Faulty sensor electronics (internal failure or water intrusion)

Symptoms

MIL/ADAS warning or message on dash (e.g., 'Check front sensor' or 'Service ADAS')
Loss or degradation of adaptive cruise, automatic emergency braking, pedestrian detection or parking assist on the right side
Stored U023E (and sometimes related U-codes) in diagnostic scanner
Intermittent operation or warning that occurs after driving over rough road or after a collision

What to check

Read all stored and pending DTCs and freeze frame data with a scan tool; note time, conditions and related U-codes
Visual inspection of right front sensor, mounting, and surrounding area for damage, water, or debris
Inspect sensor connector for corrosion, bent pins, moisture, and proper locking
Check fuses and relays related to sensor power/supply circuits
Probe sensor supply and ground at connector with key on: verify vehicle voltage and good ground
Measure CAN bus voltages at sensor connector (CAN_H and CAN_L) with key ON; check for proper idle voltages and termination

Signal parameters

Sensor power: battery voltage present with key ON (typically ~9–14 V during cranking and ~12–14 V key on) at the sensor power pin
Ground: low resistance to chassis ground (near 0 Ω) between sensor ground pin and vehicle ground
CAN bus idle voltages: CAN_H ≈ 2.5 V and CAN_L ≈ 2.5 V at sensor connector (values vary by vehicle manufacturer)
CAN differential communications: expected periodic messages from the sensor/module when system active (message frequency varies by sensor and mode)
No dominant or stuck CAN state (no permanent high or low on CAN lines) and correct termination resistance (~60 Ω across CAN_H and CAN_L combined)

Diagnostic algorithm

Confirm the code: connect a quality scan tool, record DTCs, freeze frame and live data. Check for companion codes on the same network.
Visual inspection: examine right front sensor, mounting bracket and harness for damage, corrosion, water intrusion or physical impact.
Check fuses/power: verify fuse(s) feeding the sensor are intact. Back-probe the sensor connector to confirm battery voltage on the power pin and good ground on ground pin with key ON.
Connector and wiring: disconnect sensor connector and inspect pins. Repair or replace connector if corrosion or damaged pins are present. Check continuity between sensor and the module for power, ground and CAN lines.
CAN bus test: with key ON, measure CAN_H and CAN_L voltages at the sensor connector. Use an oscilloscope or lab scope to verify proper CAN signalling and message presence. Check termination resistance across CAN_H and CAN_L.
Wiggle/road test: with scan tool monitoring, gently move harness and connector or drive to reproduce intermittent faults. Note any change in communication or new codes.
Isolate fault: if wiring and power/ground are good but communication is absent or erratic, remove/replace right front sensor with a known-good unit if available (note: many sensors require coding/calibration after replacement).
Module/Software: if a replacement sensor does not clear the condition, inspect the receiving control module and CAN bus for faults. Check for required software updates or module reprogramming from the manufacturer.
Repair and verify: perform necessary harness or sensor repairs, replace fused components if needed, clear codes and verify repair by re-checking for codes and proper operation of ADAS functions. Perform any required sensor alignment/calibration per manufacturer procedure.
Document: record all tests, repairs and final verification steps in the repair order.