P27AA: Solenoid D characterization is not accepted as correctly programmed

P27AA reports invalid characterization programming for pressure-control solenoid D in the reviewed GM source. This data-check row names GF9 C2 CB29, GR10 C5 C1356789, or CVT C1 clutch functions. Its mappings should not be borrowed from a different code family's solenoid-D row.

The data axes must remain ordered

The continuation identifies an axis-data failure when a characterization point is lower than its preceding point. The data must be nondecreasing. This is an internal calibration-validity rule, not a measurement that clutch pressure physically fell during driving.

The same programming-complete flag can also be invalidated by missing data, incomplete programming, a device-class mismatch or a checksum problem. The code identifies the rejected solenoid-D data set without uniquely identifying the reason for rejection.

Check the installed assembly identity

The source associates characterization with the valve-body assembly part number and describes programming the matching data after valve-body service. A change in hardware without correctly completed matching data is therefore a relevant investigation path, not a proven cause in every case.

The test runs during normal controller power-up initialization before ordinary time-loop operation. A road test or electrical resistance check cannot replace that data acceptance test.

Verification should establish correct hardware-to-data matching, accepted programming and no recurrence at subsequent initialization. The source lists Type A, one-trip behavior. It does not authorize replacing a clutch, valve body or controller solely because this calibration diagnostic is stored.

Source and applicability

Confirm the vehicle, transmission variant and relevant module before applying this monitor description. GM diagnostic table, PDF page 1204. GM diagnostic table, PDF page 1205.