U0191 indicates that a vehicle control module has lost communication with the TV (typically the rear seat entertainment or television module) on the controller area network (CAN). The code is set when the monitoring module does not receive expected periodic messages from the TV module for a predetermined period. This is primarily a network communication fault and does not directly affect engine operation, though related features may be inoperative.
The rear‑seat television/entertainment module itself may have failed, preventing it from sending messages on the CAN bus.
A blown fuse, bad relay, or loss of voltage/ground can leave the module powered off, causing a communication loss.
Open, shorted, or corroded wires and poor terminal connections in the TV module circuit disrupt CAN messaging.
A fault on the CAN high or low line (e.g., short to ground, short to power, or high resistance) can block messages from the TV module.
Another module (such as the HVAC or audio module) that shares the bus may fail and flood the network, preventing the TV module from communicating.
In very few cases the powertrain control module itself may be unable to process CAN traffic, but this is the least likely cause and should be investigated only after the above items are ruled out.
No. The code most often points to a problem with the TV module, its power supply, or the CAN wiring. Replacing the PCM is rarely required and is often a misdiagnosis.
Yes, the car will typically drive and run normally, but you may lose rear‑seat entertainment or audio features until the issue is resolved.
Clearing the code will turn off the MIL temporarily, but if the underlying fault remains, the code will reappear after a drive cycle.
Common causes include a blown fuse, a faulty relay, corrosion or damage to the power/ground wiring, or a failed connection at the module.