Theory Of Operation
WARNING: This page is about a different variant/trim than selected.
This diagnostic checks the performance of the hydraulic pump. The Smart Driver Unit (SDU) which is external to the Transmission Control Module (TCM) drives the hydraulic pump based upon a PWM command signal received from the Transmission Control Module (TCM). This diagnostic uses three feedback signals. The PWM driver, internal to TCM, returns a command feedback signal. The SDU returns to the TCM the hydraulic pump driver feedback signal. The TCM separately receives the hydraulic pump feedback signal confirming the pump state.