P05BDStop-Start Mode Switch Circuit Range/Performance
- Generic OBD-II code · Powertrain
- How the car detects it
- The stop-start off switch lets the driver disable automatic engine stop for the current drive. It is read directly or via another module over CAN – on Stellantis' 2025 Ram 1500 it sits in the electronic shifter module. CARB names a stop-start diagnosis as its example of an emission-neutral diagnosis, so no warning lamp is required; stop-start is usually just disabled. P05BD means the switch signal is valid but implausible. On the 2025 Ram 1500 Stellantis sets it when the engine module receives 120 presses of the stop-start button within 2 minutes over CAN – a sticking or bouncing button or a flood of messages. The first fix is an engine module software update, not parts; Stellantis warns not to replace the ignition switch for it.
- What you may notice
- Usually no noticeable symptoms
- Stop-start button not reacting or status jumping
- Code stored in the engine module
- Likely causes
- LikelyEngine module software (Stellantis: fixed by update)
- PossibleSticking or bouncing stop-start button in the shifter module
- RareVery frequent pressing by occupants
- RareShifter module faulty
- Repair
- Easy · Usually a job for a workshop.Typical cost: €0 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.