Fuel Gage Inaccurate or Inoperative. Cadillac Seville 2000

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2000 🢒 Seville 🢒 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 in Wiring Systems.

•	Refer to Fuel Level Specifications in order to verify the correct fuel level sensor readings. The Fuel Level Sensor voltage parameter is available on the scan tool in the PCM EVAP data list.

Test Description

The numbers below refer to the step number in the diagnostic table.

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

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

Step

Action

Value(s)

Yes

Did you perform the Instrument Cluster Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

Disconnect C420.
Connect the J 33431-C Signal Generator and Instrument Panel Tester between the signal circuit of the fuel level sensor and the reference low circuit of the fuel level sensor.
Turn the ignition ON, with the engine OFF.
Vary the resistance on the J 33431-C from 40-250 ohms.
Refer to Fuel Level Specifications in order to convert from resistance to fuel gage display.

Does the fuel gage display the correct fuel level?

Go to Step 4

Go to Step 3

Install a scan tool.
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 40-250 ohms.
Refer to Fuel Level Specifications in order to convert from resistance to fuel gage display.

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

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

Does the Fuel Level Sensor parameter display the correct fuel level voltage?

Go to Step 11

Go to Step 5

Inspect for the following items:

•	A high resistance in the signal circuit or the low reference circuit of the fuel level sensor between C420 and the fuel level sensor. Refer to Circuit Testing in Wiring systems.

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

•	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 to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 6

Test the reference low circuit of the fuel level sensor 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 13

Go to Step 9

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 material in the gas 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 in Engine Controls - 4.6L.

Did you complete the replacement?

Go to Step 13

Replace the instrument cluster. Refer to Instrument Cluster Replacement .