Powertrain, generic (extended)

P27AE Pressure Control Solenoid H Data Incompatible

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P27AE is the highest letter GM publicly checks for characterization data. It is absent from the 2016 eight-speed table and first appears in 17OBDG04, where H stands for the nine-speed's C6 clutch (C6789) and the ten-speed's torque converter clutch; 20OBDG04 adds mode valve B on CVTs with electronic range select. The test is identical to its siblings: one pass at TCM initialization, failure if the data are absent, of another device class, fail their checksum or show decreasing axis points, then Type A after one trip. On a ten-speed, wrong data for H mainly shows up as poor or shuddering lock-up. Since only the data are at fault, a dealer-level download, not a mechanical repair, normally ends it.

Likely causes

Replacement TCM delivered blank and not set up with valve body data

Valve body or solenoid service without data update

Corrupted solenoid H data block

Symptoms

MIL on
Shudder or missing converter lock-up on ten-speed units
Higher fuel consumption if lock-up is suppressed

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€100–400

Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

pressure control solenoid htcm

References: law.cornell.edu, gsi.ext.gm.com, gsi.ext.gm.com.