P281DPressure Control Solenoid H Control Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P281D signals that the control line of solenoid H is shorted to ground. In GM's 2016 eight-speed table H is the on/off default valve; the low flag must persist for 0.3 s within 0.5 s and one trip lights the MIL. The 2020 tables extend this to the nine- and ten-speed converter clutch valve, using about 0.5 ohm to ground as the limit and rating it Type A, and add that T87a eight-speed controllers also report an open default valve circuit as P281D, so an interrupted wire can hide behind this code. On the 2023 Corvette dual-clutch box the redundant shutdown valve of the differential is checked while switched on; a voltage below about 1.7 V at the output pin is held for 150 ms before the Type B code is stored.
- What you may notice
- MIL on after a single trip
- Transmission in default gear or fixed pressure mode
- Converter lockup or differential lock unavailable
- Likely causes
- LikelyControl wire of solenoid H shorted to ground
- PossibleOpen default valve circuit reported as low (GM T87a eight-speed)
- PossibleCoil insulation failure inside solenoid H
- 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.