P0747Pressure Control Solenoid A Stuck On
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Pressure control solenoid A sets line or clutch pressure by current; most are 'normally high', so with no current – as in limp mode – maximum pressure applies. 'A' is usually the line pressure valve, on GM clutch-to-clutch transmissions (6T, 8L, 9T) the pressure valve of clutch 1. Ford does not use P0745–P0749 but P0960–P0963. P0747 means the valve is electrically fine but pressure stays applied. On GM's clutch-to-clutch units the off-going clutch 1 does not release – slip stays below 50 rpm (9-speed, 0.8 s on loaded downshifts), and Allison flags 25 rpm or less for 0.3–1 s, both after one trip. On line pressure valves it means permanently high pressure. Harsh, abrupt shifts, a tied-up transmission and a default gear follow. GM noted false settings on 2017 8-speeds: clear and retest first.
- What you may notice
- Harsh, abrupt shifts
- Transmission ties up, engine speed drops on shifts
- Limp mode or default gear
- Check engine light
- Likely causes
- LikelyPressure or clutch valve or spool sticking (dirt, debris)
- PossibleValve body worn
- PossibleSoftware or false setting
- PossibleWrong or contaminated fluid
- RareClutch plates stuck or burnt
- 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: €400 – €3,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.