Powertrain Chart 3: Powertrain Ground Check: Description

Three vehicle grounds are essential for proper powertrain system operation. They are:

1. G104, located on the right rear corner of the block, below and to the right of the rear exhaust manifold.
2. G105, located on the left front corner of the engine on the water pump housing
3. G400, located on the right inner quarter panel, below the radio chassis and forward of the trunk compartment fuse block.

G400 is the ground location for the fuel pump. G105 is the cooling fan ground. G104 is the ground for all powertrain electronics including the PCM. Loose or poor ground connections may cause widely varying problems, from flickering telltales to PCM codes to several driveability problems. The Powertrain Ground Check should be performed when referred to by other diagnostics or when erratic or intermittent problems defy traditional diagnosis. See Fig 1. For circuit identification see Fig 2.