For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Circuit/System Description

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.

### Reference Information

#### Schematic Reference

Instrument Cluster Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Instrument Cluster Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. 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.

2. 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.

3. 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).

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Instrument Cluster or ECM replacement, setup, and programming