This code indicates the engine control module (ECM) has lost digital communication with the particulate filter pressure sensor 'B' on the controller area network (CAN) bus. The sensor monitors exhaust backpressure across the diesel particulate filter, and without this data, the ECM cannot properly calculate soot load or trigger regeneration cycles.
Corrosion, chafing, bent pins, or moisture intrusion in the sensor harness interrupt CAN signals between the pressure sensor and ECM, which is the most common root cause for communication loss.
The pressure sensor's communication circuitry has failed internally while the mechanical pressure-sensing element may remain intact, preventing digital message transmission.
Missing battery voltage, open sensor ground circuit, or reference voltage drop prevents the sensor from powering its internal communication transceiver.
Short-to-ground or open circuits in the shared twisted-pair communication lines, sometimes caused by adjacent wiring damage or other failed modules corrupting bus traffic.
Rare internal damage to the ECM's CAN transceiver circuit that prevents message reception despite intact wiring and functioning sensor; verify all other causes first before considering this.
Short trips are possible, but prolonged operation is not advised. Without pressure data, the ECM cannot verify soot load or command regeneration, risking rapid DPF clogging and possible filter damage.
Almost never. This code almost always results from wiring corrosion, connector issues, or the sensor itself. The ECM should be suspected only after exhaustive testing proves the network wiring and sensor are functional.
No. U0602 indicates a communication failure, not that the filter is full or damaged. The particulate filter is typically serviceable; repair focus should remain on the sensor circuit.
This distinguishes a secondary pressure sensor—often located downstream or monitoring a specific bank—from the primary sensor, allowing precise identification of which monitoring point has lost communication.