P2066

DTC P2066 or P2636

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptors
DTC P2066
- Fuel Level Sensor 2 Circuit Performance

DTC P2636
- Fuel Transfer Pump Flow Insufficient




Diagnostic Fault Information






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


Diagnostic Aids

Check if DTC P0461 is also set. Both DTCs P0461 and P2066 may set simultaneously if the vehicle was refueled with the ignition ON or engine RUNNING. Always refuel with the ignition OFF.


Conditions for Running the DTC


P2066
* The engine is running.
* The fuel level is greater than 32 L (8.45 gals).
* No VSS DTCs set.



P2636
* The engine is running.
* DTC P2636 runs continuously when the condition has been met



Conditions for Setting the DTC


P2066
* The ECM does not detect a change in the secondary fuel level of at least 3 liters (0.79 gallon) over a distance of 100 km (62 mi).
* The ECM detects that the primary fuel tank is less than 28 liters (7.3 gallons) and the secondary fuel tank is more than 4 liters (1 gallon) and the condition is present for 30 minutes.
* The ECM detects that the primary fuel tank is greater than 28 liters (7.3 gallons) and the secondary fuel tank is less than 4 liters (1 gallon) over a distance of 175 km (108 mi).


P2636

The ECM detects that the primary fuel tank is less than 28 liters (7.3 gallons) and the secondary fuel tank is more than 4 liters (1 gallon) and the condition is present for 30 minutes.


Action Taken When the DTC Sets

* The fuel gage defaults to empty.
* The malfunction indicator lamp (MIL) will not illuminate.
* The driver information center (DIC) displays 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.



Reference Information
Schematic Reference

Instrument Cluster Schematics (Instrument Cluster Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Instrument Cluster Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)
Special Tools

J 33431-C Instrument Panel Tester


Circuit/System Testing

1. Ignition OFF, remove the secondary fuel level sender and verify there are no obstructions interfering with the fuel level sender.

• Repair any fuel level sender interference.

2. If no interference is present, 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 between signal terminal 1 and the low reference terminal 4.

• 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 - Right Side (Service and Repair) for the 4.6L engine
* Fuel Level Sensor Replacement - Right Side (Service and Repair) for the 4.4L engine
* Control Module References (Programming and Relearning) for the ECM replacement, setup and programming