DTC P2068 4.6L LH2

DTC Descriptor

DTC P2068: Fuel Level Sensor 2 High Voltage

Diagnostic Fault Information

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

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

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 high and the ECM senses a high 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 low and the ECM senses a low 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 gage.

Conditions for Running the DTC

The ignition is ON, with the engine ON.

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Fuel Gage Description and Operation

Electrical Information Reference

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

1. Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
2. 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.

3. Ignition ON, install a 3-amp fused jumper between the secondary 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.

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

Component Testing

1. Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
2. 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 signal terminal A and the low reference terminal D.

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

Repair Instructions

DTC P2068 3.6L LY7

DTC Descriptor

DTC P2068: Fuel Level Sensor 2 High Voltage

Diagnostic Fault Information

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

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

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 high and the ECM senses a high 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 low and the ECM senses a low 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 gage.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Fuel Gage Description and Operation

Electrical Information Reference

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 4.5 volts.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
2. 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.

3. Ignition ON, install a 3-amp fused jumper between the secondary fuel level sensor signal circuit terminel A and the low reference circuit terminal D. Verify the scan tool Fuel Tank Level Remaining parameter is less than 4.5 volts.

⇒	If greater than 4.5 volts, test the secondary signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

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

Component Testing

1. Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
2. 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 signal terminal A and the low reference terminal D.

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

Repair Instructions