For 1990-2009 cars

## DTC P2067 3.6L (LY7)

### 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 P2067: Fuel Level Sensor 2 Low 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 Secondary Circuit | P2067 | P2068¹ | P2068 | P2066
Fuel Level Sensor Low Reference Circuit | -- | P2068¹ | P2068 | P2066
¹Fuel Gage Inaccurate or Inoperative

### Circuit/System Description

The primary fuel level sensor and the secondary fuel level sensor change resistance in response to fuel level. The engine control module (ECM) monitors the signal circuit of the primary fuel level sensor and the secondary fuel level sensor in order to determine the fuel level. When the fuel tanks are full, the resistances of both fuel level sensors are low, and the ECM senses a low signal voltage on both the signal circuit of the primary fuel level sensor and the signal circuit of the secondary fuel level sensor. When the fuel tanks are empty, the resistances of the fuel level sensors are high, and the ECM senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sensor and the secondary fuel level sensor in order to calculate the percentage of remaining fuel in the tanks. The ECM sends the fuel level percentage via the GMLAN serial data circuit to the instrument cluster in order to control the fuel gage. The fuel information is also used for misfire, evaporative emission (EVAP), and other on-board diagnostics.

### Conditions for Running the DTC

• | The engine keeps running.

• | The system voltage is between 10.5-18 volts.

• | The DTC P2067 runs continuously once the above condition is present.

### Conditions for Setting the DTC

• | The secondary sensor output is less than 0.25 volt.

• | The above condition is present for about 4 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 control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnosis runs and fails.

• | The control module records the operating conditions a the time of the failure. The first time the diagnosis fails, the control module stores this information into the Failure Records. If the diagnosis reports a failure on the second consecutive ignition cycle, the control module records the operating conditions a the time of the failure. The control module writes the operating conditions into the Freeze Frame and updates the Failure Records.

### Conditions for Clearing the DTC

• | The control module turns OFF the MIL after 4 consecutive ignition cycles that the diagnosis runs but does not fail.

• | A current DTC, Last Test Failed, clears when the diagnosis runs and passes.

• | A history DTC is cleared after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnosis.

• | Clear the MIL and the DTC with a scan tool.

### Reference Information

#### Fuel Level Specifications

Fuel Level Specifications

#### Schematic Reference

• | Instrument Cluster Schematics

• | Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### 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, verify that the Fuel Tank Level Remaining parameter in the ECM EVAP Data List indicates a value at or greater than 4.9 volts.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
2. Ignition ON, use a scan tool to verify that the Fuel Tank Level Remaining parameter is less than 0.2 volt.

⇒ | If the parameter is greater than 0.2 volt, test the secondary signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

3. If all circuits test normal, test or replace the secondary fuel level sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Secondary Fuel Tank Module Replacement

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

## DTC P2067 4.6L (LH2)

### 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 P2067: Fuel Level Sensor 2 Low 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 Secondary Circuit | P2067 | P2068¹ | P2068 | P2066
Fuel Level Sensor Low Reference Circuit | -- | P2068¹ | P2068 | P2066
¹Fuel Gage Inaccurate or Inoperative

### Circuit/System Description

The primary fuel level sensor and the secondary fuel level sensor change resistance in response to fuel level. The engine control module (ECM) monitors the signal circuit of the primary fuel level sensor and the secondary fuel level sensor in order to determine the fuel level. When the fuel tanks are full, the resistances of both fuel level sensors are low, and the ECM senses a low signal voltage on both the signal circuit of the primary fuel level sensor and the signal circuit of the secondary fuel level sensor. When the fuel tanks are empty, the resistances of the fuel level sensors are high, and the ECM senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sensor and the secondary fuel level sensor in order to calculate the percentage of remaining fuel in the tanks. The ECM sends the fuel level percentage via the GMLAN serial data circuit to the instrument cluster in order to control the fuel gage. The fuel information is also used for misfire, evaporative emission (EVAP), and other on-board diagnostics.

### Conditions for Running the DTC

DTC P2067 runs continuously.

### Conditions for Setting the DTC

• | The primary fuel level sensor signal voltage is less than 0.5 volt.

• | It occurs 240 times in 300 times of test.

### Action Taken When the DTC Sets

• | The fuel gage defaults to empty.

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

• | DTC P2067 is a type B DTC.

### Conditions for Clearing the DTC

DTC P2067 is a type B DTC.

### Reference Information

#### Fuel Level Specifications

Fuel Level Specifications

#### Schematic Reference

• | Instrument Cluster Schematics

• | Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### 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, verify that the Fuel Tank Level Remaining parameter in the ECM EVAP Data List indicates a value at or greater than 4.9 volts.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
2. With the ignition ON, use a scan tool to verify that the Fuel Tank Level Remaining parameter is less than 0.2 volt.

⇒ | If the parameter is greater than 0.2 volt, test the secondary signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

3. If all circuits test normal, test or replace the secondary fuel level sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Secondary Fuel Tank Module Replacement

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