LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 2002 >> Jimmy 2D Utility, Part Time, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 127 (Engine Controls - System & Component Testing) >> Fuel System (Diesel) >> Water-In-Fuel Light Always On (6.6L) >> Circuit Description
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Circuit Description

WARNING: This page does not describe the selected car, but rather 31 other vehicles, including the 2002 Saturn Vue, 2002 Pontiac Montana, 2002 Pontiac Aztek, 2002 Oldsmobile Silhouette, and 2002 Oldsmobile Bravada. However, it is still accessible from the selected car via links, so may be relevant.

The fuel manager/filter assembly consists of fuel heater, water-in-fuel sensor and a filter. Filter contains coalescer, the device that combines small droplets of water into larger ones, and filter/separator. As fuel enters filter, fuel passes first through fuel heater. Heater contains a thermostatic switch. Switch opens or closes to turn heater OFF or ON, depending on temperature of fuel. Fuel then passes through filter. Next, fuel flows through water coalescer. Here droplets of water-in-fuel combine into larger drops and fall into water reservoir in filter. When fuel flows from fuel manager/filter assembly to fuel injection pump, fuel is clean and free of water. When there is water-in-fuel filter, water-in-fuel sensor closes a switch. This completes a circuit to ground for Engine Control Module (ECM). Message center in Instrument Panel Cluster (IPC) indicates water-in-fuel when ECM commands IPC to indicate condition. This is done through data link communications, and command is available on scan tool.