The P0855 code in your 2020 Acura TLX indicates the drive input signal circuit is providing a higher voltage than expected. This affects the detection of forward driving gear selection.
Understanding High Drive Signal
The TLX's transmission position sensing uses specific voltage levels for each gear. High voltage on the drive input suggests an open ground or short to power affecting the circuit.
Common Causes of P0855
- Open circuit in signal ground
- Short to battery voltage
- Position sensor failure
- Disconnected wiring
- Connector issues
- TCM input circuit problems
Symptoms of High Drive Signal
- Drive gear always indicated
- Check engine light on
- Incorrect gear display
- Starting issues
- Transmission behavior changes
- IDS features affected
Acura TLX Electronic Controls
The TLX uses push-button gear selection with electronic transmission control. Accurate position sensing is critical since there's no mechanical connection between the buttons and transmission.