Code Definition

P1921 — Transmission Range Signal Out of Range / Implausible

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

About P1921

P1921 is a manufacturer-specific powertrain diagnostic trouble code recorded for Ford vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1921 is stored, the module has detected a plausibility fault — the measured value is in the electrical range but is not consistent with expected operating behaviour.

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.

P1921 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 Powertrain Control Module (PCM) monitors the transmission range input from the Transmission Range Sensor (TRS) or selector lever position sensor to determine the current gear position. DTC P1921 is set when the PCM detects that the transmission range signal is outside the expected voltage range, indicates multiple gear positions simultaneously, or does not correlate with vehicle operating conditions such as engine speed, vehicle speed, or commanded gear. This fault indicates an implausible or invalid range signal rather than a single circuit open or short. Symptoms can include no crank in ...

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