Circuit Description
The fuel manager/filter assembly consists of the fuel heater, the water in fuel sensor and a filter. The filter contains the coalescer, the device that combines small droplets of water into larger ones, and the filter/separator.
As fuel enters the filter, the fuel passes first through the fuel heater. The heater contains a thermostatic switch. The switch opens or closes to turn the heater OFF or ON, depending on the temperature of the fuel.
The fuel then passes through the filter. Next the fuel flows through the water coalescer. Here the droplets of water in the fuel combine into larger drops and fall into the water reservoir in the filter. When fuel flows from the fuel manager/filter assembly to the fuel injection pump, the fuel is clean and free of water.
When there is water in fuel filter, the water in fuel sensor closes a switch. This completes a circuit to ground for the engine control module (ECM).
The message center in the Instrument panel cluster indicates water in fuel when the ECM commands the instrument panel cluster (IPC) to indicate the condition. This is done through the data link (DLC) communications, and the command is available on the scan tool.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Engine Controls Schematics | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 |
Does the message center indicate water in fuel? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
3 | Perform the water-in-fuel draining procedure. Refer to Water-in-Fuel Draining . Did you complete the procedure? | Go to Step 4 | -- |
4 |
Does the message center indicate water in fuel? | Go to Step 5 | Go to Step 10 |
5 | Disconnect the water-in-fuel sensor. Refer to Water in Fuel Indicator Sensor Replacement . Does the scan tool display water-in-fuel parameter is OFF? | Go to Step 8 | Go to Step 6 |
6 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 9 |
7 | Repair short to ground in water in fuel indicator control circuit. Did you complete the repair? | Go to Step 10 | -- |
8 | Replace the water-in-fuel sensor. Refer to Water in Fuel Indicator Sensor Replacement . Did you complete the replacement? | Go to Step 10 | -- |
9 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 10 | -- |
10 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
