P2779Downshift Switch Circuit Range/Performance
- Generic OBD-II code · Powertrain
- How the car detects it
- P2779 is the plausibility fault of the downshift paddle or tip switch. GM's 2023 and 2024 TCM tables for the twin-clutch gearbox define two voltage windows for the minus paddle: 2.2–3.52 V when pulled and 3.826–4.744 V at rest. A reading caught between or around these windows for 120 s is treated as invalid and logged as Type C, no MIL. The same tables use P0816 for a minus paddle held too long. Ford's TR9070 entry in the 2024 OBD summary calls P2779 an illegal voltage on the downshift paddle input. Because the value is still inside the electrical range, suspects are a corroded contact, a drifting resistor in the switch or added resistance in the clock spring rather than a plain short. Paddle downshifts are usually locked out.
- What you may notice
- Downshift paddle inoperative
- Manual mode refused, usually no MIL
- Likely causes
- LikelyCorroded contacts or drifting coding resistor in the minus paddle
- PossibleAdded resistance in the clock spring
- RareCorrosion in the steering wheel connector
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.