You can turn the ignition off, retrieve the percentage of remaining engine oil and automatic transmission fluid life, measure the main relay circuit voltage at the ECM/TCM/IGN fuse, measure the main relay circuit voltage at the TCM/BATT fuse, disconnect the negative battery cable, remove the TCM/BATT fuse and the ECM/TCM/IGN fuse, unlock and disconnect the front engine wiring harness electrical connector, unlock and disconnect the rear engine wiring harness electrical connector, release the locking tabs and remove the ECM.