Code Definition

P31FF — ASCD Vehicle Speed Sensor Regenerative Brake

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Infiniti

About P31FF

P31FF is a manufacturer-specific powertrain diagnostic trouble code recorded for Infiniti vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P31FF is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P31FF is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Engine Control Module (ECM) or Hybrid Control Module monitors vehicle speed information used by the Automatic Speed Control Device (ASCD) in coordination with regenerative braking operation. DTC P31FF is set when the control module detects an implausible, invalid, or missing vehicle speed signal during regenerative braking conditions, or when the received speed data does not correlate with wheel speed or hybrid system inputs. This prevents accurate cruise control and regenerative brake coordination.

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