Code Definition

P1401 — Sub-Throttle Position Sensor Range/Performance

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

About P1401

P1401 is a manufacturer-specific powertrain diagnostic trouble code recorded for Toyota vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1401 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; and 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.

P1401 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

This fault code sets when the Engine Control Module (ECM) detects that the sub throttle position sensor signal is out of the expected range or does not respond correctly during throttle operation. On systems fitted with a secondary or sub throttle valve, the ECM compares this sensor against the main throttle position sensor and watches its response as the throttle opens and closes. If the voltage is inconsistent, slow to respond, or outside the calibrated range, the ECM stores this code. The driver may notice reduced power, hesitation, a limp or fail safe mode, and a check engine light.

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