P27ABPressure Control Solenoid E 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
- Solenoid E's characterization data failing the TCM's plausibility test produces P27AB. In GM's 2018 table 18OBDG04 the record is written at vehicle assembly according to the valve body part number and must be rewritten by the dealer whenever the valve body is serviced; a missing or partial block, a device class mismatch, a checksum error or falling axis values all count as failures (Type A, one trip). Valve E is clutch 5 (C45678R) on the 2016 eight-speed, clutch C3 (CB38) on the nine-speed, clutch C4 on the ten-speed and the converter clutch on the CVT. The solenoid itself may be perfect; what is wrong is the table the controller uses to drive it, so harsh or flared shifts can appear.
- What you may notice
- MIL lit
- Flare or bump on shifts using the clutch behind valve E
- On the CVT, irregular torque converter lock-up
- Likely causes
- LikelyValve body serviced without rewriting the solenoid data
- PossibleIncomplete programming session after TCM replacement
- RareSolenoid class in the data does not match the TCM calibration
- 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.