Diagnostic Instructions
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
| 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 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 onboard diagnostics.
Conditions for Running the DTC
| • | The system voltage is between 10-18 volts. |
Conditions for Setting the DTC
| • | The secondary fuel level sensor signal is about 0.35 volt. |
| • | The secondary fuel level sensor signal range is about 5 percent. |
| • | The above condition is present for about 60 seconds. |
Action Taken When the DTC Sets
| • | The fuel gage 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. |
| • | The ECM receives a clear code command from the scan tool. |
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 should indicate a value at or lower than 4 percent.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
- Ignition ON, scan tool installed, verify that the scan tool Fuel Tank Level Remaining parameter is greater than 98 percent.
| ⇒ | If less than 98 percent, test the secondary signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
- If all circuits test normal, perform the fuel level sensor component test before replacing the secondary (left) 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
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
