Code P086, Undefined Gear Ratio: Notes
WARNING: This page is about a different car, the 1995 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.
Transaxle gear ratio is calculated from ratio of turbine speed against output speed. This test checks gear ratio which is not possible to obtain under normal operating condition of transaxle, if such gear ratio is observed, Code P086 is set.