Code Definition

P1900 — Transmission Output Shaft Speed Sensor circuit intermittent

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

About P1900

P1900 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 P1900 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.

P1900 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 transmission output shaft speed sensor reports how fast the output shaft is turning, which the Powertrain Control Module uses to calculate vehicle speed, schedule gear shifts, control torque converter clutch apply, and compare against input shaft speed to monitor gear ratio and clutch slip. Depending on the application the sensor is either a variable reluctance type that generates its own AC signal as a toothed reluctor passes the pickup, or a hall effect type supplied with voltage that returns a square wave, and in both cases the signal frequency rises in proportion to shaft speed. Ford D...

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