U0133 means the vehicle’s main network has lost communication with the active roll control module, which manages the active anti-roll bar or similar roll-mitigation system. It is a communication fault rather than a sensor-performance fault, so diagnosis focuses on power, ground, wiring, and whether the module can respond on the data bus. It often appears alongside other U-codes when a broader network problem is present.
Open, shorted, corroded, or high-resistance circuits in the power, ground, or data lines to the active roll control module are the most common reason a controller stops communicating.
A blown fuse, corroded ground eyelet, or damaged power feed can shut the module down and set this code even if the module itself is otherwise good.
The module’s internal network transceiver, voltage regulator, or processor can fail, preventing it from responding on the bus.
A short, open, termination issue, or excessive electrical noise elsewhere on the bus can isolate the module and trigger lost-communication codes.
The main computer or network gateway is rarely the root cause for a single lost-communication code; consider it only after wiring, power, ground, and the module itself have been ruled out.
You can usually drive short distances, but the active roll-control system may be disabled, so avoid aggressive cornering and have it diagnosed promptly.
Erasing the code only resets the warning. If the underlying communication fault is still present, the code and symptoms will return.
Not necessarily. Many cases are caused by wiring, connector, power, or ground problems, so those should be checked before replacing the module.
Usually no. A single lost-communication code is almost always due to wiring, power, ground, or the module itself, not the PCM.