Fuel Gage Inaccurate or Inoperative. Buick Century (China) 2000

For 1990-2009 cars only

Makes 🢒 Buick 🢒 2000 🢒 Century (China) 🢒 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.

•	There is an access panel to the fuel level sender in the trunk.

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

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

This step tests for a high resistance in the signal circuit and the low reference circuit of the fuel level sensor.

DTCs will be set in the PCM when you perform this diagnostic table.

Step

Action

Value(s)

Yes

Schematic Reference: Engine Controls Schematics

Did you perform the Instrument Cluster Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

Disconnect the fuel level sensor through the access panel in the trunk.
Connect the J 33431-C Signal Generator and Instrument Panel Tester between the signal circuit of the fuel level sensor and the low reference circuit of the fuel level sensor. (female side)
Turn ON the ignition, with the engine OFF.

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

Vary the resistance on the J 33431-C from 40-250 ohms.

Does the fuel gauge move from empty to full?

Go to Step 4

Go to Step 3

Install a scan tool.
Turn ON the ignition, with the engine OFF.

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

Vary the resistance on the J 33431-C from 40-250 ohms.

Important: Turn OFF the ignition momentarily between the resistance settings in order to quickly update the scan tool display.

With the scan tool, observe the Fuel Level % parameter in the PCM EVAP data list.

Does the fuel level percent move from approximately 0 % to approximately 100 %?

Go to Step 11

Go to Step 5

Inspect for the following items:

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

•	A misaligned fuel level sender.

•	A deformed fuel tank.

Did you find and correct the condition?

Go to Step 13

Go to Step 7

Test the signal circuit of the fuel level sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 6

Test the low reference circuit of the fuel level sensor for a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

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

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

•	Foreign material in the fuel tank (ice).

Did you find and correct the condition?

Go to Step 13

Go to Step 8

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

Does the resistance change smoothly across the specified range?

40-250 ohms

Go to Diagnostic Aids

Go to Step 10

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

Did you find and correct the condition?

Go to Step 13

Go to Step 12

Replace the fuel level sensor. Refer to Fuel Level Sensor Replacement (2.5L) in Engine Controls.

Did you complete the replacement?

Go to Step 13

Replace the IPC. Refer to Instrument Cluster Replacement .