P071ATransmission Mode Switch A Circuit
- Generic OBD-II code · Powertrain
- How the car detects it
- A transmission mode switch selects an alternative shift schedule such as sport, winter or tow/haul; J2012 does not define which button is A or B. No manufacturer document available to us uses P071A–P071F: GM monitors its analog drive mode switch under its own codes (low below 21–29 % of 5 V, high from 94 %, 200 of 250 samples, two trips), which shows how such buttons are read as coded voltages. P071A is the general circuit fault of mode switch A: its state is invalid or implausible. The transmission then usually stays on its normal schedule. Low and high are P071B/P071C, switch B has P071D–P071F; the range sensor (PRNDL) is P0705 ff.
- What you may notice
- Mode A cannot be selected or stays active
- Mode indicator missing or flashing
- Transmission stays on the normal shift schedule
- Likely causes
- LikelyMode switch A faulty (selector lever or console)
- PossibleWiring or connector in the console damaged (spilled drinks, chafing)
- RareResistor coding drifted (analog buttons)
- RareControl module faulty
- Repair
- Easy · Often possible to do yourself.Typical cost: €30 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.