U0422 is a network communication code that is set when a module (most often the PCM) receives data from the Body Control Module (BCM) that it considers implausible, corrupted, or out of expected range. The fault is in the data being reported, not necessarily in the receiving module, and the code points to a communication or BCM problem rather than a sensor reading.
The BCM itself is the most common source of U0422. Internal processor or output-driver failures can cause it to broadcast implausible or corrupted data frames on the CAN bus.
Corrosion, water intrusion, bent pins, or loose terminals at the BCM connector are a frequent cause. Poor contact distorts the data signal so other modules see it as invalid.
When system voltage drops below the module's operating threshold during cranking or while running, the BCM may transmit out-of-spec data until voltage recovers.
Shorts, opens, improper termination resistance, or electrical noise on the CAN-H/CAN-L lines can corrupt messages between modules, causing other modules to flag the data as invalid.
Known software bugs in the BCM or receiving module can produce U0422. Manufacturers sometimes address these with a reflash or calibration update documented in a TSB.
In rare cases the module that flagged the data (often the PCM) has its own CAN transceiver or processor fault. This is a much less common cause than the BCM or wiring, and is usually only confirmed after BCM and wiring are ruled out.
No. The PCM is most often the module reporting the problem because it received bad data, not the source of the bad data. Replacing the PCM for U0422 is almost always the wrong repair and will not fix the issue. Focus the diagnosis on the BCM, its wiring, power supply, and the CAN bus before ever considering the receiving module.
Yes. When system voltage drops during cranking or from a failing alternator, modules can transmit corrupted or out-of-range data until voltage stabilizes, and the receiving module will log U0422 even though the BCM is otherwise fine.
Clearing the code may turn the light off temporarily, but if the underlying BCM, wiring, or network fault is still present the code will return. U0422 should be diagnosed because the same condition can affect other body functions and may coincide with other modules losing communication.
It depends on the cause. If the BCM has an internal hardware failure, replacement is typically required. If the problem is software-related, a reflash or calibration update per manufacturer procedure may resolve it. Wiring and connector repairs are also common fixes that do not require replacing the BCM at all.