What does it mean?
OBD II fault code U0416 is a generic trouble code that is defined as “Invalid Data Received From Vehicle Dynamics Control Module”, and is set when the PCM (Powertrain Control Module) detects invalid data from one or more wheel speed sensors via the ABS control module.
NOTE #1: While the above definition of code U0416 applies to most modern vehicles in terms of wheel speed/ABS faults, this code can also be set for myriad reasons that do not involve the ABS system, wheel speed sensors, stability control, or any other function that involves the stability of the vehicle.
In some cases, this code could set when faults are present in active or air-adjustable suspension systems, or where there is, at best, a tenuous relationship between exterior lighting systems and advanced driver-assist systems. Be aware though that in a large percentage of instances of this code, the root causes are never identified, and may remain unresolved throughout the affected vehicle’s useful life.
NOTE #2: It is important to note that different vehicle manufacturers use different names to describe the same thing. One case in point is the many names under which stability control systems are marketed, and this applies to ABS control modules, as well.
Many manufacturers refer to this module as the Vehicle Dynamics Control Module, or something similar, so be sure to consult reliable service information for the affected vehicle to avoid confusion about the terminology used to describe the same thing by different names.
As this code relates to wheel speed sensors and their relationship to ABS braking functions and overall vehicle stability, however, the PCM collects data from a host of sensors that include yaw rate sensors, lateral accelerometers, pitch/roll sensors, and others such as the steering angle sensor to determine whether the vehicle is stable while moving.
In practice, the PCM will recognize an unstable condition when it detects (at a minimum)- That large discrepancies exist between the rotational speeds of individual wheels A large lateral acceleration is occurring, as reported by lateral accelerometers and/or one or more yaw rate sensors This information is compared to the throttle opening, road speed, engine speed, the currently selected gear, and both the rate and angle of steering inputs, which in a fully functional dynamics control system, should yield calculated wheel speeds that will almost exactly match the actual wheel speeds as measured and reported by the wheel speed sensors.
If the PCM determines that a dangerous condition, such as a potential skid is present, it will use the ABS system to apply selective braking forces (via the stability control system) to individual wheels to force the vehicle into a line that is dictated by the steering angle sensor.
For this system to work as intended/designed though, the PCM needs to receive accurate data from all the wheel speed sensors, since this data is the basis upon which corrective action or remedial strategies are built by the PCM and other implicated control modules, such as the ABS control module.
One practical example of implausible data (as it relates to input data from wheel speed sensors), would be if the rotational speeds as measured and reported on one driving wheel and one non-driving wheel vary by more than a maximum allowable threshold.
For instance, if one driving wheel is reported to be rotating twice as fast as a non-driving wheel, but no wheels are locked up under braking, or are not spinning under acceleration, the PCM will recognize that the inputs received from at least one wheel speed sensor are implausible. When this happens, the PCM will recognize that is cannot control the stability of the vehicle effectively, and it will set code U0416 and illuminate one or more relevant warning lights.
Note though that the PCM will typically also deactivate the ABS system, as well as others such as stability control, traction control, cruise control, and every other system that uses th