P2721 is logged when the control line of solenoid D reads too high, typically because it touches battery positive. GM's 2016 six-speed tables describe it as circuit high covering an open or a short to power, set after 0.3 s in one trip, so on those units an open line can land here too. The 2023 Corvette dual-clutch TCM tests with the driver on and sets it when the sense voltage exceeds a limit that rises with supply, about 0.7 V below 11.5 V and 1.1 V above 15.5 V (Type A); Ford's TR9070 calls this shorted load. Subaru bulletin 16-149-25 lists P2721 on 2020-2023 Legacy, Outback and Crosstrek with the TR580 CVT: condensation reaches the control valve connector, and a new control valve and connector cover fix it.
Medium severity. Can I keep driving?Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.
Symptoms
- MIL on and fail-safe operation
- Shift shock or missing gears
- Fault may follow wet weather or washing
Most likely causes
- Moisture in the control valve connector (Subaru TR580)
- Control wire shorted to a supply circuit
- Open circuit on units that report it as high (GM six-speed)
- Faulty solenoid D or TCM driver
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P2721 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 7: Transmission
- 21: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2721?
Drive as little as possible and gently. If the transmission slips or stays in one gear, go slowly to a repair shop or call for a tow truck.
What causes code P2721?
The most common causes are: moisture in the control valve connector (Subaru TR580); control wire shorted to a supply circuit; open circuit on units that report it as high (GM six-speed).
Related codes
- P2716Pressure Control Solenoid D Electrical
- P2718Pressure Control Solenoid D Control Circuit/Open
- P2719Pressure Control Solenoid D Control Circuit Range/Performance
- P2720Pressure Control Solenoid D Control Circuit Low
- P2730Pressure Control Solenoid E Control Circuit High
- P0963Pressure Control Solenoid A Control Circuit High
- P2763Torque Converter Clutch Pressure Control Solenoid Control Circuit High
Sources
- static.nhtsa.gov: MC 11013504 0001
- gsi.ext.gm.com: 23OBDG07
- gsi.ext.gm.com: 16OBDG03 Transmission Diagnostics
- fordservicecontent.com: OBDSM2400OUTPUT 16Jul2024 WSM final V2 MCS7001
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.