Fuel Gage Inaccurate or Inoperative. Chevrolet Chevrolet C-Series Medium Duty Truck B7 2000

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2000 🢒 Chevrolet C-Series Medium Duty Truck B7 🢒 Body and Accessories 🢒 Instrument Panel, Gauges, and Console 🢒 Fuel Gage Inaccurate or Inoperative

Diagnostic Aids

•	Ensure that the fuel level is in the same range as the customer concern.

•	For intermittent diagnosis, refer to Testing for Intermittent Conditions and Poor Connections .

•	Use the fuel sender resistance (0-90 ohms) to verify the fuel level sender operation. When the fuel tank is empty the sender resistance is 0 ohms and when the fuel tank is full the sender resistance is 90 ohms.

Step

Action

Value(s)

Yes

Disconnect the fuel sender connectors.
Connect the J 33431-C Signal Generator and Instrument Panel Tester between the signal circuit of the fuel level sender and a good ground.
Turn the ignition ON, with the engine OFF.

Important: Verify the J 33431-C resistance settings with a DMM.

Vary the resistance on the J 33431-C from 0 - 90 ohms. The fuel gauge should indicate empty at 0 ohms and full at 90 ohms.

Does the fuel gauge display the correct fuel level?

Go to Step 2

Go to Step 3

Inspect for the following items:

•	A poor connection at the harness connector of the fuel level sender. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

•	A misaligned fuel level sender.

•	A deformed fuel tank.

Did you find and correct the condition?

Go to Step 10

Go to Step 5

Test the signal circuit of the fuel level sender for an open, for a short to ground or for a high resistance between the fuel level sender and the IPC. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 4

Test the fuel level sender case ground for an open or for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 7

Remove the fuel level sender.
Inspect for the following items:

•	A stuck fuel level sender (i.e. the fuel strainer interfering with the sender float arm)

•	Foreign materials in the fuel tank (ice)

Did you find and correct the condition?

Go to Step 10

Go to Step 6

With the J 39200 DMM, measure the resistance of the fuel level sender while moving the float arm.
Observe both the analog and the digital displays on the DMM.

Does the resistance change smoothly across the specified range?

0-90 ohms

Go to Diagnostic Aids

Go to Step 8

Inspect for poor connections at the harness connector of the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

Replace the fuel level sender. Refer to Fuel Sender Assembly Replacement in Engine Controls - 7.4L or Cat® Medium Duty Diesel Engine Manual - 7.2L.

Did you complete the replacement?

Go to Step 10

Replace the IPC. Refer to Instrument Cluster Replacement .