U0016 indicates that the voltage on the medium-speed Controller Area Network (CAN) bus is lower than expected, often due to a short to ground, open circuit, or a faulty module. This bus typically connects body control modules, infotainment systems, and other non-powertrain components.
Chafed, pinched, or corroded wires in the medium-speed CAN bus circuit, especially near connectors or areas of movement, can cause a low voltage condition.
A defective body control module (BCM), anti-lock brake system (ABS) module, or other module can pull the bus voltage low or fail to communicate properly.
Loose, bent, or corroded terminals at module connectors or splice points can create high resistance or intermittent shorts.
Insufficient battery voltage can cause modules to operate erratically and affect CAN bus signal levels.
A missing or out-of-spec termination resistor on the medium-speed CAN bus can cause signal reflections and voltage abnormalities.
While rare, a failed PCM/ECM can affect the medium-speed CAN bus, but this is typically a last-resort diagnosis after all other modules and wiring have been ruled out.
You may be able to drive, but the vehicle could experience loss of important functions like ABS, stability control, or instrument cluster. It is best to diagnose and repair promptly to avoid safety issues.
Clearing the code will only turn off the warning light temporarily. If the underlying issue (e.g., wiring fault or bad module) is not repaired, the code will return and the problem may worsen.
Almost never. The PCM is rarely the cause of a medium-speed CAN bus low code. Most often the issue is a wiring problem or a faulty body control module, ABS module, or other bus participant. Replacing the PCM without proper diagnosis is usually a waste of money.
The medium-speed CAN bus (typically 125 kbps) connects non-powertrain modules such as the body control module, instrument cluster, door modules, and infotainment system. It handles functions like lighting, locks, windows, and climate control.