U0320 indicates that the engine or primary network controller has detected a software or calibration mismatch with the Power Steering Control Module (PSCM). This means the PSCM is either running incorrect software for the vehicle, was not properly configured after installation, or its identification message is being misread on the data bus. The result is typically a stored diagnostic trouble code and possible degradation or loss of power steering assist.
The module may contain the wrong factory programming or corrupted calibration data for the vehicle’s specific configuration, often after a repair or failed update.
Installing a new or salvage PSCM without performing required vehicle-specific programming leaves the module incompatible with the network.
Opens, shorts, or high resistance in the high-speed CAN circuits can distort module identification messages and trigger an incompatibility fault.
Low voltage, blown fuses, or poor ground connections can prevent the module from initializing fully, causing the PCM to read an invalid software status.
A defective processor or memory within the power steering module can make its software unreadable, resulting in a persistent mismatch code.
This is rare; the engine computer could falsely reject a compatible PSCM if its own recognition tables are corrupted, but only after the PSCM and network have been ruled out.
Clearing the code will not fix an underlying calibration or hardware fault. The warning and steering symptoms will almost certainly return immediately or on the next key cycle.
Not necessarily. Many cases are resolved by reprogramming the existing module or installing the correct calibration. Replacement should only follow confirmation that the module hardware has failed or is the wrong part number.
No. A failed PCM is an extremely unlikely cause for U0320. This code almost always points to the power steering control module’s software, calibration, or network communication, not the engine computer.
A recent dead battery or jump start can corrupt module memory. If the PSCM lost its calibration data, it may trigger this code until the module is properly reprogrammed.