U026D — Lost Communication With Image Processing Sensor I

Causes

• Faulty image processing sensor/module (internal failure)
• Open/short/intermittent wiring between sensor and network gateway/ECU
• Corroded or loose connector(s) at the sensor or inline junctions
• Missing or intermittent sensor power or ground
• CAN bus (or other vehicle-network) wiring fault: opens, shorts, or poor termination
• Network gateway, junction box, BCM or ECU fault preventing message routing

Symptoms

• Stored U026D trouble code and possibly related U-codes
• Message on dash: camera unavailable / ADAS unavailable / Check Surround/Camera System
• No image or intermittent image on infotainment or driver display
• One or more driver assistance features (lane-keep, AEB, adaptive cruise) disabled or degraded
• Possible CAN-bus related warnings or other modules showing communication errors
• System may work intermittently or only after ignition cycles

What to check

• Read all stored codes on all modules; note freeze frame and time stamps; record any other U-codes present
• Visually inspect camera/module and harness for damage, corrosion, water ingress, or crushed wiring; check connectors are fully seated and locked
• Check for blown fuses or relays that supply the camera/module power
• With ignition ON, verify sensor power and ground at the module connector with a multimeter (compare to vehicle battery voltage and chassis ground)
• Inspect the network wiring: check continuity between the sensor connector and gateway/ECU connector, and inspect for chafing or pinched sections
• Measure CAN or network bus resistance (with ignition OFF): two-terminal end-to-end resistance should be approx. 60 ohms for classic CAN (two 120-ohm terminators) — value significantly different indicates termination/short problem

Signal parameters

• Classic CAN (typical): recessive idle — CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (both equal); dominant — CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
• Typical CAN bus end-to-end resistance ≈ 60 ohms (two 120-ohm terminators in parallel)
• Common CAN data rates: 125 kbps, 250 kbps, 500 kbps (verify vehicle-specific rate with manufacturer data)
• CAN-FD and higher-speed buses may use different timing/levels — consult OEM documentation
• Automotive Ethernet (if used for camera): link status and PHY negotiation must be present; physical-layer voltages and signaling differ from CAN — use manufacturer diagnostics or Ethernet test equipment to verify link and packet data
• Logical: expect periodic status messages/IDs from the image sensor when awake; absence of IDs indicates no transmission or gateway filtering

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