Fuel Gage Inaccurate or Inoperative. GMC Truck Savana

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2003 🢒 Savana - AWD 🢒 Body and Accessories 🢒 Instrument Panel, Gages, and Console 🢒 Fuel Gage Inaccurate or Inoperative

Fuel Gage Inaccurate or Inoperative Single Tank

Diagnostic Aids

•	Verify 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 readings for the fuel level sensor. The Fuel Tank Level Remaining % parameter is available on the scan tool in the PCM Enhanced EVAP data list.

Test Description

The numbers below refer to the step numbers 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 set in the PCM when you perform this diagnostic table.

Step

Action

Value(s)

Yes

Schematic Reference: Instrument Cluster Schematics

Connector End View References: Instrument Panel, Gages, and Console Connector End Views , Powertrain Control Module Connector End Views in Engine Controls-4.3L or Powertrain Control Module Connector End Views in Engine Controls-4.8L, 5.3L, and 6.0L

Did you perform the Instrument Cluster Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

Disconnect C101.
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 on the female terminal side of the connector.
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.

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 level percentage.

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 Tank Level Remaining % parameter in the PCM Enhanced EVAP data list.

Does the Fuel Tank Level Remaining % parameter display the correct fuel level percentage?

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 to Connector Repairs in Wiring Systems.

•	A high resistance in the signal circuit or the low reference circuit between the fuel level sender and C101

•	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 sender for a high resistance between C101 and the PCM. 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 low reference circuit of the fuel level sender for a high resistance between C101 and the PCM. 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:

•	The fuel level sensor is stuck, perhaps due to an interference with the fuel strainer.

•	The fuel tank contains foreign material, for instance, ice.

Did you find and correct the condition?

Go to Step 13

Go to Step 8

With the DMM, measure the resistance of the fuel level sender 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 to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

Replace the fuel level sender. Refer to appropriate procedure:

•	Fuel Level Sensor Replacement in Engine Controls-4.3L

•	Fuel Level Sensor Replacement in Engine Controls- 4.8L, 5.3L, and 6.0L

Did you complete the replacement?

Go to Step 13

Replace the IPC. Refer to Instrument Cluster Replacement .

Did you complete the replacement?

Go to Step 13

Important: Program the replacement PCM.

Replace the PCM. Refer to the appropriate procedure:

•	Powertrain Control Module Replacement in Engine Controls-4.3L

•	Powertrain Control Module Replacement in Engine Controls-4.8L, 5.3L, and 6.0L

Did you complete the replacement?

Go to Step 13

Use the scan tool in order to clear the PCM DTCs.
Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Fuel Gage Inaccurate or Inoperative Dual Tank

Diagnostic Aids

•	Verify 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 readings for the fuel level sensor. The Fuel Tank Level Remaining % parameter is available on the scan tool in the PCM Enhanced EVAP data list.

Test Description

The numbers below refer to the step numbers 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 set in the PCM when you perform this diagnostic table.

Step

Action

Value(s)

Yes

Schematic Reference: Instrument Cluster Schematics

Did you perform the Instrument Cluster Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

Disconnect C101.
Connect a jumper wire between the signal circuit of the primary fuel level sender and the signal circuit of the secondary fuel level sender - female terminal side.
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 on the female terminal side of the connector.
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.

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 level percentage.

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 Tank Level Remaining % parameter in the PCM Enhanced EVAP data list.

Does the Fuel Tank Level Remaining % parameter display the correct fuel level percentage?

Go to Step 11

Go to Step 5

Inspect for the following items:

•	A poor connection at the harness connector of the fuel level senders

Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

•	A high resistance in the primary and secondary signal circuits or the primary and secondary low reference circuits between the fuel level sender and C101

•	A misaligned fuel level sender

•	A deformed primary or secondary fuel tank

Did you find and correct the condition?

Go to Step 13

Go to Step 7

Test the signal circuits of the primary and secondary fuel level senders for a high resistance between C101 and the PCM. 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 low reference circuit of the primary and secondary fuel level senders for a high resistance between C101 and the PCM. 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 senders.
Inspect for the following items:

•	The fuel level sender is stuck, perhaps due to an interference with the fuel strainer.

•	The fuel tank contains foreign material, for instance, 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 senders 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 to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

Replace the fuel level sender. Refer to appropriate procedure:

•	Fuel Level Sensor Replacement in Engine Controls-4.3L

•	Fuel Level Sensor Replacement in Engine Controls-4.8L, 5.3L, and 6.0L

Did you complete the replacement?

Go to Step 13

Replace the IPC. Refer to Instrument Cluster Replacement .

Did you complete the replacement?

Go to Step 13

Important: Program the replacement PCM.

Replace the PCM. Refer to the appropriate procedure:

•	Powertrain Control Module Replacement in Engine Controls-4.3L

•	Powertrain Control Module Replacement in Engine Controls-4.8L, 5.3L, and 6.0L

Did you complete the replacement?

Go to Step 13

Use the scan tool in order to clear the PCM DTCs.
Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2