Fuel Gage Inaccurate or Inoperative Single Tank

The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuit of the fuel level sender in order to determine fuel level. The sender consists of a variable resistor that changes resistance based on the fuel level in the tank. The ECM/PCM monitors the voltage across the sender resistance in order to determine the fuel level. The ECM/PCM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel, in percent. The ECM/PCM sends the fuel level percent via the serial data circuit to the instrument cluster in order to control the fuel gage.

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connectors at the fuel level sensor.
2. Ignition OFF, test for less than 1.0 ohm between the low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM/PCM.

3. Install a Signal Generator and Instrument Panel Tester between the signal circuit terminal 4 and ground.
4. Ignition ON, vary the signal generator resistance between 40 and 250 ohms. Verify that the scan tool Fuel Level Sensor parameter displays a range that varies between 0.5 and 4.5 volts as the signal generator resistance changes.

⇒	If not within the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the ECM/PCM.

5. Vary the signal generator resistance between 40 and 250 ohms. Verify that the fuel gage displays a range that varies between empty and full as the signal generator resistance changes.

⇒	If the gage is incorrect, replace the IPC.

6. If all circuits test normal, test or replace the fuel level sensor.

1. Ignition OFF, remove the fuel level sender.
2. While sweeping the fuel level sensor through its full range of motion, test for a minimum value less than 41 ohms and a maximum value greater than 119 ohms of resistance between the signal terminal 4 and the low reference terminal 2.

⇒	If not within the specified range, replace the fuel level sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Fuel Gage Inaccurate or Inoperative Dual Tank

The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine fuel level. Each sender consists of a variable resistor that changes resistance based on fuel level in both tanks. The ECM/PCM monitors the voltage across both sender resistances in order to determine the fuel level. The ECM/PCM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to calculate the total remaining fuel, in percent. The ECM/PCM sends the fuel level percent via serial data circuit to the instrument cluster in order to control the gage.

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connectors at the primary and secondary fuel level sensors.
2. Ignition OFF, test for less than 1.0 ohm between the primary fuel level sensor low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM/PCM.

3. Ignition OFF, test for less than 1.0 ohm between the secondary fuel level sensor low reference circuit terminal 2 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM/PCM.

4. Jumper the primary fuel level sensor signal circuit terminal 4 to the secondary fuel level sensor signal circuit terminal 4. Install a Signal Generator and Instrument Panel Tester between the jumpered signal circuits and ground.
5. Ignition ON, vary the signal generator resistance between 40 and 250 ohms. Verify that both the scan tool Fuel Level Sensor parameter and the Fuel Level Sensor Rear Tank parameter displays a range that varies between 0.5 and 4.5 volts as the signal generator resistance changes.

⇒	If not within the specified range, test the signal circuit for an open/high resistance. If the circuits test normal, replace the ECM/PCM.

6. Vary the signal generator resistance between 40 and 250 ohms. Verify that the fuel gage displays a range that varies between empty and full as the signal generator resistance changes.

⇒	If the gage is incorrect, replace the IPC.

7. If all circuits test normal, perform the fuel level sensor component test before replacing either the primary or secondary fuel level sensor.

1. Ignition OFF, remove the primary and secondary fuel level senders.
2. While sweeping the primary fuel level sensor through its full range of motion, test for a minimum value less than 41 ohms and a maximum value greater than 119 ohms of resistance between the signal terminal 4 and the low reference terminal 2.

⇒	If not within the specified range, replace the primary fuel level sensor.

3. While sweeping the secondary fuel level sensor through its full range of motion, test for a minimum value less than 41 ohms and a maximum value greater than 119 ohms of resistance between the signal terminal 4 and the low reference terminal 2.

⇒	If not within the specified range, replace the secondary fuel level sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.