P0827Up and Down Shift Switch Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- Many selectors read tap-up and tap-down over one shared wire with voltage steps or a resistor network; P0826–P0828 cover this shared circuit, P0815/P0816 the single directions. P0827 means the shared circuit voltage is too low – a short to ground, depending on the design an open on a pulled-up input, or a switch held closed. The only documented user is Ram's 2025 heavy-duty truck with the 6.7 Cummins and eight-speed TorqueFlite HD: a 2026 bulletin lists P0827 with P0826 and P085F and the MIL; the display shows N although P is engaged, the engine cannot be switched off and limp mode is possible. The fix was new transmission software. Saab reports the same state under P0826 (below 0.2 V for 30 s), GM under P0826.
- What you may notice
- Tap or manual shifting not working
- MIL (Ram)
- N shown although in P, engine cannot be switched off (Ram)
- Likely causes
- LikelySignal wire shorted to ground
- PossibleTap switch held closed or selector assembly faulty
- PossibleTransmission software (Ram 2025)
- RareControl module faulty
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.