U0696 indicates that the vehicle's control module has lost communication with the particulate filter pressure sensor labeled 'C'. This is a network (U‑code) fault, meaning the sensor is not transmitting or receiving data on the CAN bus as expected.
The sensor itself may have an internal fault (open circuit, short, or drifted output) that prevents it from sending valid data on the CAN bus.
Damaged wires, chafed insulation, corroded pins, or a loose connector can interrupt communication between the sensor and the control module.
A short to voltage, short to ground, or high resistance on the CAN_H/CAN_L lines can cause loss of communication with multiple nodes, including the sensor.
The module responsible for reading the sensor may have a communication transceiver failure, though this is less common than sensor or wiring problems.
While the powertrain control module could theoretically fail to send/receive the correct messages, this is rare for U0696 and should be considered only after sensor, wiring, and bus checks are negative.
No. The PCM/ECM is seldom the cause of a lost communication code with a specific sensor. Replacing it without first checking the sensor, its wiring, and the CAN bus usually does not resolve the issue and can lead to unnecessary expense.
Driving is possible, but the vehicle may enter limp‑in mode, have reduced power, and the DPF may not regenerate properly, which can lead to increased back‑pressure and potential long‑term damage. It is advisable to diagnose and repair the fault promptly.
Clearing the code only removes the stored fault; if the underlying communication failure persists, the code will return after the next drive cycle or when the conditions that trigger the fault are met.