This code indicates that the HVAC control module has lost its data connection with the right rear temperature actuator 'B'. The actuator is a small electric motor that regulates air temperature for the right rear passenger zone, and this code means it is no longer responding to commands over the vehicle's communication network.
The internal electronics or motor of the actuator itself have failed, preventing it from communicating on the data bus. This is the most common cause.
An open circuit, short to power, or short to ground on the communication wire (often a LIN bus) between the HVAC module and the actuator.
Poor electrical contact at the actuator connector or the HVAC module connector can interrupt the data signal.
The main climate control module has internally failed and is no longer transmitting the communication signal, though this is rare.
Usually not. The HVAC module is typically just reporting that it cannot hear back from the actuator. The fault lies with the actuator itself or the wiring in the vast majority of cases.
Yes, this code does not affect the drivability or safety of the vehicle. However, the right rear passenger will not be able to control their temperature, which may cause comfort issues.
It is an electric motor that opens and closes a blend door inside the rear HVAC ducting, mixing hot and cold air to achieve the temperature selected by the passenger.
Yes, vehicles with multi-zone climate control use multiple actuators. 'B' simply designates a specific actuator in the right rear zone, distinguishing it from others like the left rear or front actuators.