The instrument cluster displays the fuel level based on the information from the engine control module (ECM). The ECM converts the data from the fuel level sensors to a fuel level signal. The ECM sends the fuel level signal via a High Speed CAN-Bus signal to the body control module (BCM). The BCM then sends the information via a Low Speed CAN-Bus signal to the instrument cluster to display the fuel level. If the fuel level falls below 11% the instrument cluster switches the low fuel level indicator on.

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 ON, observe the scan tool ECM - Fuel Level Sensor parameter. The reading should be 1-4 V and changes with fuel level is changing.

⇒	If the reading do not change, refer to Circuit/System Testing

2. Ignition ON, perform the Instrument Cluster Gauge Sweep test with the scan tool, verify that the fuel level gage sweeps from its low to high position.

⇒	If the fuel level gage does not sweep, replace the P16 Instrument Cluster.

3. Command the All Indicators test ON and OFF with the scan tool, verify that the low fuel level indicator turns ON and OFF.

⇒	If the low fuel level indicator always stays on or always off, replace the P16 Instrument Cluster.

4. If the fuel level gage does sweep and the low fuel level indicator changes between ON and OFF, replace the K20 Engine Control Module (ECM).

1. Ignition OFF, disconnect the harness connector at the G12 Fuel Pump.
2. Ignition OFF, test for less than 5 Ω 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 K20 Engine Control Module (ECM).

3. Ignition ON, verify the scan tool ECM - Fuel Level Sensor parameter is greater than 4 V.

⇒	If less than the specified range, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and the low reference circuit terminal 2. Verify the scan tool ECM - Fuel Level Sensor is less than 1 V.

⇒	If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

5. If all circuits test normal, test or replace the appropriate sensor.

Static Test

1. Ignition OFF, disconnect the harness connector at the G12 Fuel Pump.
2. Test for 20-300 Ω between the signal terminal 1 and the low reference circuit terminal 2.

⇒	If not within the specified range, replace the G12 Fuel Pump.

3. Test for infinite resistance between each terminal and the sensor housing/case.

⇒	If less than the specified value, replace the G12 Fuel Pump.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.