P2066
DTC P2066
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P2066
- Fuel Level Sensor 2 Performance
Diagnostic Fault Information
Circuit/System Description
The primary fuel level sensor and the secondary fuel level sensor change resistance in response to the fuel level. The engine control module (ECM) monitors the signal circuit of the primary fuel level sensor, the secondary fuel level sensor, and the type of fuel in order to determine the fuel level. For regular unleaded fuel the ECM monitors a constant signal. When the vehicle has approximately 20% or greater ethanol for E85 fuel applications, the ECM controls a pulse cycle signal where it monitors the signal and calculates the fuel level percentage only during the on pulse of approximately 100 ms.
When the fuel tanks are full, the sensor resistances of both fuel level sensors are low and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sensor and 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 circuit of the primary fuel level sensor and the secondary fuel level sensor in order to calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via the serial data circuit to the instrument cluster in order to control the fuel gauge.
This diagnostic tests for a stuck fuel level sensor signal. The ECM sets this DTC if the fuel level sensor signal appears to be stuck based on a lack of signal variation expected during normal operation.
Conditions for Running the DTC
* The engine is running.
* Fuel level is greater than 32 liters (8.5 gallons).
Conditions for Setting the DTC
* The ECM detects a change in fuel level less than 3 liters (0.8 gallon) over a distance greater than 282 km (175 miles).
* The vehicle is at rest and the primary fuel tank increases by 3 liters (0.8 gallon) and the secondary fuel tank does not decrease by 3 liters (0.8 gallon) when the transfer pump is on greater than 500 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.
Reference Information
Schematic Reference
Instrument Cluster Schematics Instrument Cluster Schematics
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
Instrument Cluster Description and Operation Instrument Cluster
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Component Testing
1. Ignition OFF, remove the secondary fuel level sender and verify there are no obstructions interfering with the fuel level sender.
• If any interference is present, repair the fuel sender interference.
2. Ignition OFF, disconnect the harness connector at the secondary fuel level sensor.
3. While sweeping the fuel level sensor through its full range of motion, test for a minimum resistance value of less than 41 ohm and a maximum value greater than 119 ohm between the signal terminal C and the low reference terminal B.
• If not within the specified range, replace the secondary fuel level sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Fuel Level Sensor Replacement (Regular Cab w/26 Gal Tank) Fuel Level Sensor Replacement (Regular Cab w/26 Gal Tank)Fuel Level Sensor Replacement (Extended Cab w/26 Gal Tank) Fuel Level Sensor Replacement (Extended Cab w/26 Gal Tank)Fuel Level Sensor Replacement (Regular Cab w/34 Gal Tank) Fuel Level Sensor Replacement (Regular Cab w/34 Gal Tank) for the 4.3L engine
* Fuel Level Sensor Replacement (15 Reg Cab With 26 gal Tank) Fuel Level Sensor Replacement (15 Ext/Crew Cab With 26 gal Tank) Fuel Level Sensor Replacement (15 Reg/Ext/Crew Cab w/34 gal Tank) Fuel Level Sensor Replacement (25 Ext/Crew Cab w/26 gal Tank) for the 4.8L, 5.3L, 6.0L, and 6.2L engines
* Fuel Level Sensor Replacement for the 6.6L engine
* Control Module References Control Module References for ECM replacement, programming and setup