U0208 means another control module, often the PCM, can no longer communicate with the seat control module over the vehicle's CAN network. This is a communication fault, not necessarily a failure of the seat motors themselves. As a result, power, memory, heated, or ventilated seat functions may stop working.
The seat control module itself is the most common cause. Internal electronics can fail and drop off the CAN bus, even though the seat motors may still test good individually.
Open, shorted, pinched, or corroded wires in the harness running to the seat are common, especially where the harness flexes under or inside the seat.
A blown fuse, faulty relay, poor ground connection, or damaged power feed can prevent the module from waking up and communicating.
An open or short in the high- or low-speed CAN bus lines, or a short between them, can isolate the seat module from the rest of the network.
A rare cause is a problem in the module that reports the code, such as the PCM or gateway, but this should only be considered after wiring, power, ground, and the seat module itself have been ruled out.
Yes. This code does not affect engine performance or braking safety, but seat adjustment, memory, heating, or ventilation features may not work.
Usually no. The PCM is rarely the actual cause of a lost-communication code directed at the seat control module. Most cases are caused by the seat module, wiring, or power/ground issues.
A weak or recently disconnected battery can cause temporary communication codes. If the code returns after the battery is fully charged and modules complete their wake-up cycle, it should be diagnosed as a real fault.
Clearing the code may turn off the warning light temporarily, but if the underlying communication fault remains, the code will usually return.