What P0747 means
The transmission computer sees hydraulic pressure that stays on when it should let go, on the circuit run by pressure control solenoid A. That can make shifts bang hard, and the transmission may briefly bind as if two gears are engaged. A valve sticking from dirt or worn fluid is the most common cause.
How the engine computer 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.
Written from public technical sources and not yet checked by a mechanic. How we write these pages
Symptoms
- Harsh, abrupt shifts
- Transmission ties up, engine speed drops on shifts
- Limp mode or default gear
- Check engine light
Common causes
- Pressure or clutch valve or spool sticking (dirt, debris) Most likely
- Valve body worn Possible
- Software or false setting Possible
- Wrong or contaminated fluid Possible
- Clutch plates stuck or burnt Less likely
How to diagnose P0747
- Have the transmission module read with a scanner that supports your transmission, and note every code stored.
- Ask about service bulletins and software updates. On some transmissions this code can set falsely, so a shop may clear it and retest first.
- Check that the fluid level is right and the fluid is the correct type. Wrong or contaminated fluid can make valves stick.
- A shop can command the solenoid on a scanner and watch pressure or clutch slip to confirm the fault.
- If a valve is sticking, the repair is usually the solenoid or valve body. Burnt clutches mean a transmission repair.
Vehicles that report P0747 most
| Vehicle | Years | Reports | Share | Median miles |
|---|---|---|---|---|
| Chevrolet Silverado 1500 | 2020–2024 | 18 | — | |
| GMC Sierra 1500 | 2022–2023 | 9 | — | |
| Chevrolet Silverado 2500 | 2021–2024 | 7 | — | |
| Chevrolet Suburban | 2022–2024 | 6 | — | |
| GMC Sierra 2500 | 2020–2024 | 5 | — | |
| GMC Sierra 3500 | 2020–2024 | 4 | — | |
| Chevrolet Silverado 3500 | 2020–2024 | 4 | — | |
| GMC Yukon XL | 2021–2023 | 3 | — |
Counts of owner complaints to the NHTSA that mention P0747 (65 in total), not failure rates: popular models get more complaints simply because more of them are on the road. Models with fewer than 3 complaints are left out.
Reading the code
- P
- Powertrain
- 0
- Generic (SAE) code
- 7
- Transmission
- 47
- Specific fault
Questions drivers ask
Can I drive with code P0747?
Keep driving to a minimum. If shifts are harsh, the car jerks or slows down hard during a shift, or it's stuck in one gear, have it towed. If it shifts normally, drive gently to a shop.
Will my car pass an emissions inspection with P0747?
Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.
Often reported together
Codes that owners mention in the same NHTSA complaints as P0747. They can point to a shared cause, so it's worth checking them together.
This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.