P27B6Internal Control Module Transmission Speed Sensor Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- P27B6 is the supervision check on the transmission speed signals. GM's 2024 heavy-duty TCM tables work out the output speed that should result from turbine speed and the current gear ratio and set the code, MIL on the first trip, when the raw output speed deviates by 10 or more for at least 10 seconds while output speed is at least 50, the range is not neutral and no shift is under way. Ford's summaries list it as non-MIL; the 2024 issue names tie-up protection (UDS P0701_92) and unintended deceleration (P0701_96) on its eight- and ten-speed automatics. Ford TSB 18-2211 dealt with a lit MIL and P27B6 on 2018 F-150 trucks with 2.7, 3.5 or 5.0 L engines built until 4 May 2018 by reprogramming the PCM. Pure sensor circuit faults carry P0715 or P0720.
- What you may notice
- MIL or wrench light
- Harsh or abrupt deceleration events
- Fixed gear or limited shifting
- Likely causes
- LikelyModule software (Ford TSB 18-2211, PCM reprogramming)
- PossibleTurbine or output speed sensor delivering an implausible signal
- RareDamaged tone wheel or interference on sensor wiring
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €0 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.