P2805Transmission Range Sensor A/B Correlation
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Both range sensor signals are valid on their own, yet they do not agree. Many designs output two complementary pulse-width signals whose duty cycles must add up to 100 %. GM reads signal A in the transmission module and signal B in the engine module and sets P2805 as Type A when the sum is off by more than 4.849 % (2020 table) or 5.2 % (2025) for 1 s of 1.5 s. Ford allows plus or minus 4 % on its six- and ten-speed automatics (2024) and used the same principle on the DPS6 (2012). Audi bulletin 2051686 for 2016-2017 A6 links P280500 with a no-start and a gearbox message, cured by a new drive position sensor G676 plus TCM. Single-signal faults are P0705-P0709 and P2800-P2804.
- What you may notice
- MIL and gearbox warning on
- Engine will not start or selector position not accepted
- Substitute gear or limp operation
- Likely causes
- LikelyRange sensor with one drifting output
- PossibleAdded resistance or poor ground in one of the two signal paths
- RareFault in the reading control module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.