P2803 indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the Transmission Range Sensor B circuit, meaning the sensor signal is out of the expected range.
The sensor itself may have failed internally, producing a high voltage signal.
Open circuits, short-to‑voltage, or corrosion in the sensor wiring can cause a high voltage reading.
Improperly seated pins or a connector that is not fully engaged can create intermittent high‑voltage signals.
An over‑voltage condition on the sensor supply line (e.g., a faulty regulator) can drive the sensor signal high.
A malfunction within the PCM’s range‑sensor input circuit can falsely report a high voltage, but this is uncommon.
It is possible but rare. Most cases are due to the sensor, its wiring, or a voltage supply problem. Replacing the PCM should be a last resort after confirming the other components are good.
The vehicle may stay locked in Park or Neutral, preventing normal driving. Continuing to drive can cause additional wear on the transmission control system.
Often the sensor itself is the faulty part, but sometimes cleaning the connector or repairing damaged wires resolves the issue. Replace only if the sensor fails the bench test or a substitution confirms it.
It means the PCM is reading a voltage level higher than the maximum expected for the sensor signal, indicating an electrical fault rather than a mechanical one.