GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 TopKick C-Series (Conventional) C6/C7/C8 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Water-in-Fuel Lamp Inoperative

Diagnostic Aids
    • The water in fuel sensor illuminates the Water in Fuel indicator when there is water in the fuel system. Perform the Water in Fuel Draining procedure before performing the following test steps to accurately determine if a malfunction exists. Refer to one of the following procedures:
       -  Water-in-Fuel Draining for the 6.6L (LBZ and LLY) engine
       -  Water-in-Fuel Draining for the 6.6L (LMM) engine
       -  Water-in-Fuel Draining for the 7.8L engine
    • For intermittent diagnosis, refer to Testing for Intermittent Conditions and Poor Connections .

Step

Action

Yes

No

Schematic Reference: Driver Information System Schematics

Connector End View Reference: Master Electrical Component List

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Start and idle the engine.
  2. Observe the water in fuel indicator in the message center.

Does the water in fuel indicator illuminate in the message center?

Go to Diagnostic Aids

Go to Step 3

3
  1. Turn the engine OFF.
  2. Disconnect the water in fuel sensor.
  3. Connect a 3-ampere fused jumper wire between the signal circuit of the water in fuel sensor and a good ground.
  4. Turn the ignition ON, with the engine OFF.

Does the water in fuel indicator illuminate in the message center?

Go to Step 4

Go to Step 5

4
  1. Turn the ignition OFF.
  2. Connect a 3-ampere fused jumper wire between the signal circuit of the water in fuel sensor and the ground circuit of the water in fuel sensor.
  3. Turn the ignition ON, with the engine OFF.

Does the water in fuel indicator illuminate in the message center?

Go to Step 8

Go to Step 6

5

Test the signal circuit of the water in fuel sensor for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Test the ground circuit of the water in fuel sensor for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

7

Inspect for poor connections at the harness connector of the message center. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the water in fuel sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace the message center. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

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10

Replace the water in fuel sensor. Refer to one of the following procedures:

    •  Water in Fuel Indicator Sensor Replacement for the 6.6L (LBZ and LLY) engine
    •  Water in Fuel Indicator Sensor Replacement for the 6.6L (LMM) engine
    • Water in Fuel Sensor Replacement for the 7.8L engine

Did you complete the replacement?

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2