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 (IPC) indicates water in fuel when the ECM commands the 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 | Turn ON the ignition, with the engine OFF. Does the battery indicator illuminate in the message center in the Instrument cluster? | Go to Step 3 | Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and Console |
3 | Start and run the engine. Does the message center in the instrument panel cluster (IPC) indicate that there is water in the fuel? | Go to Water-in-Fuel Draining | Go to Step 4 |
4 | Observe the water in fuel parameter of the scan tool. Does the scan tool indicate the lamp is being commanded ON? | Go to Step 13 | Go to Step 5 |
5 |
Does the scan tool indicate the lamp is being commanded ON? | Go to Step 10 | Go to Step 6 |
6 | Connect a 3-amp fused jumper wire between the control circuit of the water in fuel sensor and a good ground. Refer to Using Fused Jumper Wires in Wiring Systems. Does the scan tool indicate the lamp is being commanded on? | Go to Step 9 | Go to Step 7 |
7 | Test the control circuit of the water in fuel sensor for an open. refer to Testing for Continuity in Wiring Systems. Did you find a problem? | Go to Step 8 | Go to Step 11 |
8 | Repair open in the water in fuel sensor control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
9 | Repair open condition in water in fuel sensor ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
10 |
Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
11 |
Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
12 | Replace the water-in-fuel sensor. Refer to Water in Fuel Indicator Sensor Replacement . Did you complete the replacement? | Go to Step 14 | -- |
13 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 14 | -- |
14 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 1 |
