P2805 indicates the two redundant signal circuits from the transmission range sensor (gear position/neutral safety switch) do not agree with each other. The PCM/TCM compares these signals and sets the code when the reported positions conflict, which can affect shift logic, starter enable, and gear indication.
The most common cause is internal wear, contamination, or circuit failure inside the transmission range sensor/neutral safety switch, causing one or both signal circuits to read incorrectly.
Open, shorted, or corroded wiring and poor terminal contact in the sensor harness can cause one signal circuit to drift or fail, creating a mismatch between the A and B signals.
If the sensor is loose, incorrectly installed, or the shifter cable/linkage is out of adjustment, the internal contacts may not align with the actual gear selector position.
Worn or binding shifter linkage, cable stretch, or transmission detent problems can leave the selector between positions, producing conflicting sensor readings.
Rarely, a control module may misinterpret valid sensor signals due to software issues or internal hardware failure; this should be considered only after sensor, wiring, and adjustment checks are ruled out.
It can affect starting and shifting, and may put the transmission in limp mode. It is not usually an immediate safety hazard, but it should be diagnosed soon to avoid drivability problems.
Often the sensor is the cause, but wiring, connector, and adjustment issues are also common. Verify those before replacing the sensor to avoid an unnecessary repair.
A PCM/TCM failure causing this code is uncommon. Most P2805 faults are caused by the sensor, its wiring, or adjustment. PCM replacement is usually the wrong first step.
Short trips may be possible, but shifting may be abnormal and the vehicle may not start reliably. It is best to diagnose the problem before extended driving.