P281BPressure Control Solenoid H Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P281B stands for an open control circuit of solenoid H. GM's 2020 tables apply it to the converter clutch valve of nine- and ten-speed automatics and to the T93 eight-speed default valve; an impedance of about 200 kilohm, seen for 0.3 s of 0.5 s, sets a Type A fault in one trip. On the T87a eight-speed controllers an open default valve circuit is filed as P281D instead. In the 2023 Corvette dual-clutch box H is the redundant shutdown valve of the differential lock; with the output off, the driver tries to hold the pin low with a tiny current, and if it succeeds the load is missing, confirmed after 150 ms as Type B. Broken wires, a backed-out terminal or an open coil are the usual causes; converter lockup or the differential lock is then lost.
- What you may notice
- MIL on after one trip
- No converter clutch lockup, higher engine speed at cruise
- Limited-slip differential disabled (Corvette dual-clutch)
- Likely causes
- LikelyOpen coil in solenoid H
- PossibleTerminal pushed back or loose in the connector
- PossibleBroken wire in the internal or external transmission harness
- 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: €80 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.