Chevrolet Equinox Service Manual: Non-Shifting Clutch Function Verification Description Automatic Transmission Unit

The 6T30/40/45/50 transmission uses a pressure control system to apply and releaseclutches during shifts. The transmission control module (TCM) controls pressure commandsto the pressure control solenoids.

As normal wear of the transmission clutches occur, the TCM performs a clutch functionverification. The TCM momentarily commands a clutch on at a low pressure. The clutchfunction verification is conducted on smooth roads when the transmission is not shiftingand engine torque is consistent and positive.

When a clutch function verification is occurring, a slight bump or drag may be detectedmomentarily. The clutch function verification will occur a few times over severalminutes and will not repeat again for a thousand or more miles. This is a normalcondition and no repair attempts should be performed.

The clutch function verification will be performed sooner for a particular clutchif the TCM detects it is producing frequent poor shift control.