Drivers first notice a sudden warning light on the instrument cluster, often accompanied by a message such as “Stability Control Off” or “Power‑Steering Assist Reduced.” In many cases the MIL (Malfunction Indicator Lamp) flashes or stays illuminated, and the vehicle may feel less stable during cornering or abrupt lane changes. Some owners report that the power‑steering feel becomes heavy for a few seconds before returning to normal. These cues appear without any change in engine performance, because the fault belongs to the motion‑control network rather than the powertrain.
The Motion Control Module B (often part of the vehicle’s chassis‑control network) continuously sends steering angle, yaw‑rate, and wheel‑speed data to the stability‑control ECU. Corrupted packets—caused by voltage spikes, EMI, or internal memory errors—trigger the U0573 flag because the receiving ECU cannot validate the information.
Corroded pins, loose crimped terminals, or broken shielded pairs in the CAN‑bus segment that links Module B to the rest of the network can alter bit patterns. Even a single high‑resistance joint can cause the receiving node to reject the data as invalid.
If Module B’s firmware has become corrupted (e.g., after an interrupted re‑flash) or is outdated relative to the vehicle’s main control unit, the data structures no longer match the expected format. The discrepancy is logged as invalid data.
Moisture ingress, solder‑joint fatigue, or failed memory cells inside Module B can produce random or stuck‑at‑zero values. The module continues to transmit, but the content fails checksum verification, prompting the U0573 code.
A voltage drop below the module’s minimum operating range—often due to a failing battery‑monitor circuit or a weak alternator regulator—can cause the module to reset intermittently, sending incomplete frames that the network flags as invalid.
– Connect a manufacturer‑specific scan tool capable of reading chassis‑control modules.
– Record all pending and stored codes; clear the U0573 to verify if it returns after a drive cycle.
– Using the scan tool, command a live data stream from Motion Control Module B.
– Verify that the module transmits valid steering‑angle, yaw‑rate, and wheel‑speed values.
– If the tool reports “no response” or “invalid data,” the fault is communication‑related.
– Visually inspect the CAN‑bus harness between Module B and the stability‑control ECU.
– Check for corrosion, frayed wires, or pinched connectors.
– Perform a resistance test (should be < 30 Ω) and a continuity check on each shielded pair.
– Measure supply voltage at the module’s power pins while the ignition is on (typically 12.0 V ± 0.5 V).
– Confirm that ground points have less than 0.1 Ω resistance to chassis ground.
– If firmware version is older than the vehicle’s main control unit, update Module B using the dealer‑level re‑flash procedure.
– Verify successful programming by re‑reading the version number and confirming no communication errors.
– For isolated solder‑joint cracks or moisture damage, a qualified electronics repair shop may re‑ball the board and reseal the case.
– Note that such repairs are temporary; internal failures often recur.
– When communication remains invalid after wiring, voltage, and firmware checks, replace Motion Control Module B.
– Use a VIN‑matched unit programmed to the vehicle’s exact software map.
Estimated costs
Repairing a Motion Control Module B is rarely a permanent fix when the underlying cause is moisture intrusion or internal memory degradation. The cost of board‑level repair—typically $200‑$350 for a specialist—does not include the risk of repeat failures, which can lead to recurring safety‑system shutdowns.
For vehicles older than eight years, the original module’s design may lack modern shielding and is more prone to corrosion. In such cases, a direct replacement eliminates the need for repeated diagnostics and reduces vehicle downtime.
Modern control modules are integrated with security, immobilizer, and vehicle‑network authentication systems. That complexity makes correct programming as critical as the hardware itself. Replacing the module with a unit that is pre‑programmed to the exact VIN ensures seamless communication with all safety subsystems, eliminates the need for on‑site coding, and provides a warranty that covers both hardware and software integrity.
Flagship One brand positioning
Flagship One specializes in VIN‑matched control modules, delivering a plug‑and‑drive solution backed by a lifetime warranty. Our modules are pre‑programmed to your vehicle’s specifications before they leave the warehouse, so installation is limited to a simple bolt‑in and a brief verification scan. By sourcing the replacement from Flagship One, you avoid dealer programming delays and gain the confidence of a module that has passed rigorous functional testing.
Flagship One provides VIN-programmed, OEM engine and powertrain control modules backed by lifetime warranty. Units arrive pre-programmed to your vehicle’s specifications for plug-and-drive installation.