P0816Downshift Switch Circuit
- Generic OBD-II code · Powertrain
- How the car detects it
- Tap-up and tap-down switches let the driver choose gears on an automatic (selector gate, buttons or paddles). GM, Ford and Saab all treat a shift request that appears where it is impossible – in park or neutral, at Ford also reverse – or that stays on implausibly long as a stuck switch. P0816 is the mirror of P0815 for the downshift switch. GM's 2025 table sets it when 'tap down' stays on for more than 1 s (100 ms raster, over 9 V), the 2018 hybrid table after 2 s in P/N or 655 s in drive, type C without MIL; Saab's 9-4X after 1 s in P/N or 10 minutes in a drive range; Ford's SelectShift when the switch is closed in P, R or N, without MIL. On selectors with a resistor network a short to positive in the downshift branch sets P0816. Manual shifting is disabled, automatic operation stays normal.
- What you may notice
- Manual down shifting not working
- Transmission stays in the normal automatic mode
- No check engine lamp
- Likely causes
- LikelyDownshift switch or paddle sticking or faulty
- PossibleSignal wire shorted to positive
- PossibleSelector assembly faulty
- RareBody or transmission module
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.