DTC P2068. Cadillac STS 2006

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2006 🢒 STS 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 DTC P2068

DTC P2068 4.6L and 4.4L

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.

DTC Descriptor

DTC P2068: Fuel Level Sensor 2 High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Fuel Level Sensor Reference Voltage Circuit	P2067	--	--	P2066
Fuel Level Sensor Signal Circuit	P2067	P2068	P2068	P2066
Fuel Level Sensor Low Reference Circuit	--	P2068	P2068	P2066

The primary (left) fuel level sender and the secondary (right) fuel level sender changes resistance based on fuel level. The engine control module (ECM) monitors the signal circuits of the primary (left) fuel level sender and the secondary (right) fuel level sender in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level senders are high and the ECM senses a high signal voltage on both the signal circuits of the primary (left) fuel level sender and the secondary (right) fuel level sender. When the fuel tanks are empty, the resistances of the fuel level senders are low and the ECM senses a low signal voltage. The ECM uses the signal circuits of the primary (left) fuel level sender and the secondary (right) 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 gage.

Conditions for Running the DTC

The ignition is ON, with the engine ON.

Conditions for Setting the DTC

•	The secondary fuel level signal is greater than 4.5 volts.

•	The above condition is present for greater than 20 seconds.

Action Taken When the DTC Sets

•	The fuel gage defaults to empty.

•	The driver information center (DIC) illuminates the FUEL LEVEL LOW message.

•	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.

•	The ECM receives a clear code command from the scan tool.

Reference Information

Schematic Reference

•	Instrument Cluster Schematics

•	Engine Controls Schematics for the 4.6L engine

•	Engine Controls Schematics for the 4.4L engine

Connector End View Reference

•	Instrument Panel, Gages, and Console Connector End Views

•	Engine Control Module Connector End Views for the 4.6L engine

•	Engine Controls Connector End Views for the 4.4L engine

Description and Operation

Fuel Gage Description and Operation

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

With the scan tool installed and the ignition ON, the Fuel Tank Level Remaining parameter in the ECM EVAP Data List indicates a value at or greater than 98 percent.

Circuit/System Testing

Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal D and ground.

⇒	If greater than 1 ohm, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

Ignition ON, install a 3-amp fused jumper between the secondary (right) fuel level sensor signal circuit terminal A and the low reference circuit terminal D. Verify the scan tool Fuel Tank Level Remaining parameter is less than 4 percent.

⇒	If greater than 4 percent, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

If all circuits test normal, perform the fuel level sensor component test before replacing the secondary (right) fuel level sensor.

Component Testing

Ignition OFF, disconnect the harness connector at the secondary (right) fuel level sensor.
While sweeping the secondary (right) 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 signal terminal A and the low reference terminal D.

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

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Secondary Fuel Tank Module Replacement for the 4.6L engine

•	Secondary Fuel Tank Module Replacement for the 4.4L engine

•	Control Module References for the ECM replacement, setup, and programming

DTC P2068 3.6L LY7