P2631 Alfa Romeo OBD2 reports a sensor fault, replacement of the sensor is unlikely to resolve the underlying problem. The fault is most likely to be caused by the systems that the sensor is monitoring, but might even be caused by the wiring to the sensor itself.
Accelerator Pedal Position Sensor 1 Circuit Low and P2127 - Accelerator Pedal Position Sensor 2 Circuit Low would lead you to suspect a defective accelerator pedal position sensor.
Vehicle Speed Sensor (VSS) Out of Self Test Range Indicates the VSS input signal is out of Self Test range. If the PCM detects a VSS input signal any time during Self Test, a DTC P1501 will be set and the test will abort. Noisy VSS input signal from Radio Frequency Interference/ Electro-Magnetic Interference (RFI/EMI) external sources such as ignition wires, charging circuit or after market equipment. Check for VSS input to be 0 mph when vehicle transmission is in Park.
P2631 meaning and repair processes are the same for all Alfa Romeo models.
P2631 Alfa Romeo Trouble Repair Process:
When you turn on the ignition, the Service Engine Soon or Check Engine P2631 Alfa Romeo light should flash briefly, indicating that the OBD system is ready to scan your vehicle for any malfunctions. After this brief flash, the light should stay off while you drive as long as no problems are detected. You'll be glad to know that your vehicle is equipped with an early warning system that could save you time, money, and fuel in addition to helping protect the car!
It works by having a slightly higher than normal opening temperature, which still works the same way as regular ones, but it also has a heating coil, which means the ECU can open the thermostat earlier and keep the engine slightly cooler.