P27ADPressure Control Solenoid G Data Incompatible
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P27AD flags the stored data for pressure control solenoid G as not matching the hardware. GM's 2016 eight-speed table names G the torque converter clutch solenoid and sets the code in one trip. In the 2017 to 2020 tables G is clutch C5 (C57R) on the nine-speed, the line pressure valve on the ten-speed and, only on CVTs with electronic range select, mode valve A; there it is a Type A fault checked at controller start. The 2025 table 25OBDG03A no longer lists G, ending its characterization checks at F. When the line pressure valve of a ten-speed is affected, shift feel can change across all gears. Reloading the valve body data with a scan tool is the usual repair.
- What you may notice
- MIL illuminated
- Converter clutch or range mode problems, depending on transmission
- General shift harshness on ten-speed units
- Likely causes
- LikelySolenoid G data missing after TCM programming
- LikelyValve body changed without matching data
- RareTCM calibration for a different transmission variant
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €100 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.