U0266 indicates the powertrain control module has lost communication with an image processing sensor designated as 'Sensor B'. This sensor is typically part of an advanced driver assistance system (ADAS) such as forward collision warning, lane departure warning, or adaptive cruise control. When the control module cannot receive expected data from this sensor within the required time frame, it sets this trouble code.
The sensor itself has failed internally and no longer transmits data over the network. This is the most common cause and the component most likely to require replacement.
Damaged, chafed, or corroded wiring between the sensor and control module can interrupt the communication bus or power supply circuits.
Poor connection at the sensor connector or module connection can cause intermittent or complete loss of communication.
A failed fuse supplying power to the image processing sensor will prevent it from operating and communicating on the network.
Rare, but occasional software bugs in the receiving control module may cause it to fail to recognize valid data from the sensor.
A general network issue affecting the bus the sensor communicates on could theoretically affect multiple modules, though this is uncommon.
Almost never. Lost-communication codes are caused by the failed component, its wiring, or connections in the overwhelming majority of cases. The PCM itself is rarely at fault. Insist on a thorough inspection of the sensor circuit before accepting a PCM replacement.
Generally yes, but with caution. Many ADAS safety features relying on that sensor may be disabled. Use extra care with lane changes, braking, and parking. Have the issue diagnosed before relying on features like automatic emergency braking.
Possibly, depending on vehicle architecture. Many backup cameras are integrated into the same image processing module. However, backup camera issues can also stem from other causes such as the camera itself, the infotainment system, or related wiring.
U0265 indicates lost communication with Image Processing Sensor A, while U0266 indicates lost communication with Sensor B. The two codes refer to different sensor locations or functions. Both codes can be set simultaneously if they share a common power supply, ground, or network circuit.