P05D1Driver Mode Select Switch A Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- The driver mode select switch (tour, sport, eco, snow, off-road, towing) changes engine and transmission maps such as shift points, pedal map and cylinder deactivation, so CARB requires it to be monitored as an input. GM reads switch A as an eight-position resistor ladder in the body module and sets P05D1–P05D3 in its 2025 tables when a condition is present for 4 s within 5 s, type B with warning lamp after two trips. A fault blocks mode selection; the vehicle stays in its basic mode. P05D1 means the signal is below the lowest valid window: GM petrol body modules below 1.327 V, diesel below 0.528 V. Typical are a signal shorted to ground or a shorted switch.
- What you may notice
- Drive mode cannot be changed, vehicle stays in normal mode
- Mode display missing or jumping back
- Check engine light (GM after two trips)
- Likely causes
- LikelySignal line to the body module shorted to ground (chafing in the console)
- PossibleSwitch shorted internally (moisture, spilled drink)
- PossibleConnector at the switch damaged
- RareBody module input
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €30 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.