2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2464
6. If all circuits test normal, test or replace the IMS.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Note:
* Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (See: Transmission and Drivetrain/Automatic
Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/6L45/6L50/6L80/6L90 - Automatic
Transmission/Control Solenoid Valve and Transmission Control Module Assembly Inspection) before replacing any internal transmission
components.
* Perform the Service Fast Learn Adapts (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing and
Inspection/Programming and Relearning) following all transmission repairs.
* Manual Shift Shaft Position Switch Replacement (See: Powertrain Management/Computers and Control Systems/Sensors and Switches -
Computers and Control Systems/Transmission Position Sensor/Switch/Service and Repair/6L45/6L50/6L80/6L90 - Automatic Transmission
)for internal mode switch (IMS) replacement.
* Control Module References (See: Testing and Inspection/Programming and Relearning)for control solenoid valve assembly replacement,
setup, and programming.
P2066
DTC P2066
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/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).
