Fuel Gage Inaccurate or Inoperative. Isuzu Isuzu MD F-Series 2005

For 1990-2009 cars only

Makes 🢒 Isuzu 🢒 2005 🢒 Isuzu MD F-Series 🢒 Body 🢒 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 .

•	Refer to Fuel Level Specifications in order to verify the correct readings for the fuel level sensor. The Fuel Level Sensor % parameter is available on the scan tool in the engine control module (ECM) Fuel System 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 ECM when you perform this diagnostic table.

Step

Action

Values

Yes

Schematic Reference: Instrument Cluster Schematics

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Disconnect the fuel level sensor.
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 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 .
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 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 .
Refer to Fuel Level Specifications in order to convert from resistance to fuel level percentage.

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 Sensor % parameter in the engine control module (ECM) Fuel System data list.

Does the scan tool 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 .

•	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 to Wiring Repairs .

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 to Wiring Repairs .

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 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?

0-90 ohms

Go to Diagnostic Aids

Go to Step 10

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

Did you find and correct the condition?

Go to Step 13

Go to Step 12

Replace the fuel level sensor. Refer to Fuel Sender Assembly Replacement .

Did you complete the replacement?

Go to Step 13

Replace the instrument panel cluster (IPC). Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 13

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

Did you complete the replacement?

Go to Step 13

Use the scan tool in order to clear the 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 .

•	Refer to Fuel Level Specifications in order to verify the correct readings for the fuel level sensors. The Fuel Level Sensor % parameter is available on the scan tool in the Fuel System 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 circuits and the low reference circuits of the fuel level sensors.

DTCs will set in the engine control module (ECM) when you perform this diagnostic table.

Step

Action

Values

Yes

Schematic Reference: Instrument Cluster Schematics

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Disconnect the primary and the secondary fuel level sensors.
Connect a jumper wire between the signal circuit of the primary fuel level sensor and the signal circuit of the secondary fuel level sensor.
Connect the J 33431-C Signal Generator and Instrument Panel Tester between the signal circuit of the fuel level sensors and the low reference circuit of the fuel level sensors on the female terminal side of the connector.
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 .
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 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 .
Refer to Fuel Level Specifications in order to convert from resistance to fuel level percentage.

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 engine control module (ECM) Fuel Level Sensor percent parameter in the Fuel System data list.

Does the scan tool 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 sensors--Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

•	A misaligned primary fuel level sender or secondary fuel level sender

•	A deformed primary fuel tank 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 fuel level sensors for a high resistance. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

Go to Step 13

Go to Step 6

Test the low reference circuits of the fuel level sensors for a high resistance. Refer to Circuit Testing and to Wiring Repairs .

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 sensors are stuck, perhaps due to an interference with the fuel strainer.

•	The fuel tanks contain 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 each 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 for each fuel level sensor?

0-90 ohms

Go to Diagnostic Aids

Go to Step 10

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

Did you find and correct the condition?

Go to Step 13

Go to Step 12

Replace the fuel level sensor that did not respond correctly to the last inspection. Refer to Fuel Sender Assembly Replacement .

Did you complete the replacement?

Go to Step 13

Replace the instrument panel cluster (IPC). Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 13

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

Did you complete the replacement?

Go to Step 13

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

Did you correct the condition?

System OK

Go to Step 2