Code Definition

P1901 — TSS Circuit Intermittent Malfunction

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

About P1901

P1901 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1901 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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.

P1901 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 P1901 fault code indicates that the Transmission Control Module (TCM) or Powertrain Control Module (PCM) has detected an intermittent issue with the Turbine Shaft Speed (TSS) sensor circuit. The TSS sensor monitors the rotational speed of the transmission's input shaft, and its signal must remain stable for proper transmission operation. If the sensor signal fluctuates unexpectedly or drops out intermittently, the control module logs this fault.

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