P0756Shift Solenoid B Performance/Stuck Off
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- A shift solenoid is an electrically switched valve in the valve body; together the solenoid states select the gear, and the module checks the result by gear ratio, slip or a pressure switch – the pattern of wrong gears shows which solenoid hangs off or on. P0756 means solenoid B is commanded on but its clutch or valve does not follow. GM's 6T70 commands second gear as a test and counts a ratio of 2.7–3.0 three times; GM's T43 2.246–2.482; GM 4-speeds recognise the pattern 4-3-3-4 and go straight to third gear with maximum pressure; Allison checks its pressure switch for 5 s – all after one trip. Ford's 'functionally failed off' covers the whole clutch circuit; an 8F35 bulletin calls for a transmission overhaul.
- What you may notice
- Gears missing or skipped
- Pulling away in the wrong gear, weak acceleration
- Limp mode or gear lock-out
- Check engine light
- Likely causes
- LikelyShift spool in the valve body sticking (dirt, debris)
- PossibleInternal leak or clutch fault in the circuit
- PossibleSolenoid mechanically sluggish or screen clogged
- PossibleFluid level or quality wrong
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €200 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.