P281B code meaning
Pressure Control Solenoid H Control Circuit/Open
Powertrain system Generic code P28xx codes Check engine light
What P281B means
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.
P281B at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P281B
- MIL on after one trip
- No converter clutch lockup, higher engine speed at cruise
- Limited-slip differential disabled (Corvette dual-clutch)
Common causes of P281B
- Most likelyOpen coil in solenoid H
- PossibleTerminal pushed back or loose in the connector
- PossibleBroken wire in the internal or external transmission harness
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Pressure control solenoid hWiring harness
What each part of P281B means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 8 | Area: transmission. |
| 1B | The exact fault in that area. |
What to do next
- Note P281B and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P281B
What does P281B mean?
P281B means "Pressure Control Solenoid H Control Circuit/Open". P281B stands for an open control circuit of solenoid H. It is a generic code, so it means the same on every make.
Is it safe to drive with P281B?
Drive gently and only to a workshop. With P281B the car can go into limp mode (reduced power) to protect itself.
Will P281B fail an emissions test?
Yes, it can. P281B is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P281B to fix?
Difficulty: hard. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will P281B clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.