2010 Cadillac CTS Sedan AWD V6-3.0L Page 1785

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1785

Diagnostic Fault Information

Circuit/System Description

The primary fuel level sender and the secondary fuel level sender changes resistance based on fuel level. The engine control module (ECM)

monitors the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to determine the fuel level. When the fuel

tank is full, the resistances of both fuel level senders are low and the ECM senses a low signal voltage on both the signal circuits of the primary fuel

level sender and the secondary fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are high and the ECM

senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sender and the secondary fuel level sender in order to

calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via serial data circuit to the instrument cluster in

order to control the fuel gauge.

Conditions for Running the DTC

* The engine is running.

* No fuel level sensor signal failure present.

* The fuel level state is stable.

Conditions for Setting the DTC

* The ECM detects a difference between the engine consumed fuel and change of the fuel level signal of less than 1 L (0.26 gallons) over a

range of 30 L (7.92 gallons) or 45.6 percent of the secondary fuel tank.

* The above condition is present for about 300 seconds.

Action Taken When the DTC Sets

* The fuel gauge defaults to empty.

* The low fuel indicator illuminates.

* The ECM records the operating conditions at the time that the diagnostic test fails. The ECM displays the failure information in the Failure

Records on the scan tool.

Conditions for Clearing the DTC

* The DTC becomes history when the conditions for setting the DTC are no longer present.

* The history DTC clears after 40 malfunction-free warm-up cycles.

Diagnostic Aids

A partially filled fuel tank and filling the fuel tank with the ignition ON or engine RUNNING may cause an inaccurate or erratic fuel gauge. This

condition may cause a fuel system DTC to set and the fuel gauge to default to empty. Refer to Fuel Gauge Description and Operation (See:

Instrument Panel, Gauges and Warning Indicators/Description and Operation/Fuel Gauge).

Reference Information

Schematic Reference

Instrument Cluster Schematics (See: Diagrams/Electrical Diagrams/Instrument Panel, Gauges and Warning Indicators/System Diagram/Instrument

Cluster Schematics)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views)

Description and Operation

Fuel Gauge Description and Operation (See: Instrument Panel, Gauges and Warning Indicators/Description and Operation/Fuel Gauge)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit

Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)