U0025
WysokiLow voltage on the negative line of the low-speed CAN bus (CAN Low).
OBD-II (EN): CAN Low Voltage Below Threshold
Fault code U0025 means the voltage on the negative line of the low-speed CAN bus is too low. It can cause communication problems between modules, manifesting as flickering gauges or non-functional windows. The cause is often damaged wiring or corroded connectors.
Symptoms
Flickering gauges, non-functional power windows and door locks, intermittent warning lights, module communication problems.
Possible causes
Wiring harness issues (chafing, insulation damage) Corrosion of contacts in CAN bus connectors Faulty CAN bus control module (e.g., BCM, PCM)
Affected systems
Tags and synonyms
Sources and further reading
Does code U0025 require professional diagnostics?
The code alone is not enough. To find the cause, you need to read live data, check freeze frame conditions, and compare with vehicle behavior. Book a diagnostic session.