P27AD code meaning
Pressure Control Solenoid G Data Incompatible
Powertrain system Generic code P27xx codes Check engine light
What P27AD means
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.
P27AD at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 1.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P27AD
- MIL illuminated
- Converter clutch or range mode problems, depending on transmission
- General shift harshness on ten-speed units
Common causes of P27AD
- Most likelySolenoid G data missing after TCM programming
- Most likelyValve body changed without matching data
- Less likelyTCM calibration for a different transmission variant
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Pressure control solenoid gTCM
What each part of P27AD means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 7 | Area: transmission. |
| AD | The exact fault in that area. |
What to do next
- Note P27AD 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 P27AD
What does P27AD mean?
P27AD means "Pressure Control Solenoid G Data Incompatible". P27AD flags the stored data for pressure control solenoid G as not matching the hardware. It is a generic code, so it means the same on every make.
Is it safe to drive with P27AD?
Drive gently and only to a workshop. With P27AD the car can go into limp mode (reduced power) to protect itself.
Will P27AD fail an emissions test?
Yes, it can. P27AD 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 P27AD to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 1.5 hours of work. This is a job for a workshop.
Will P27AD clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.