8. The vacuum/pressure gauge on the J 41413-200 and the FTP parameter on the scan tool should both show vacuum.
锟斤拷If the vacuum/pressure gauge shows vacuum, but the FTP parameter does not show vacuum, replace the FTP sensor.
锟斤拷If neither the FTP parameter nor the vacuum/pressure gauge shows vacuum, repair the restriction in the purge path. Refer to Evaporative
Emission Control System Description (See: Powertrain Management/Computers and Control Systems/Description and
Operation/Evaporative Emission Control System Description).
9. Verify that the vacuum increases to the abort limit on the scan tool or more than 3.2 volts, and the values are similar between the scan tool
and the vacuum/pressure gauge on the J 41413-200.
锟斤拷If the values are not similar, or the voltage did not reach 3.2 volts, replace the FTP sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Fuel Tank Pressure Sensor Replacement (1500 LWB - 117.3L (31 gal) Tank + E85) (See: Powertrain Management/Computers and Control
Systems/Fuel Tank Pressure Sensor/Service and Repair/Fuel Tank Pressure Sensor Replacement (1500 LWB - 117.3L (31 Gal) Tank + E85))Fuel
Tank Pressure Sensor Replacement (2500 Series) (See: Powertrain Management/Computers and Control Systems/Fuel Tank Pressure
Sensor/Service and Repair/Fuel Tank Pressure Sensor Replacement (2500 Series))Fuel Tank Pressure Sensor Replacement (1500 Series) (See:
Powertrain Management/Computers and Control Systems/Fuel Tank Pressure Sensor/Service and Repair/Fuel Tank Pressure Sensor Replacement
(1500 Series))Fuel Tank Pressure Sensor Replacement (1500 SWB - 98.4L (26 gal) Tank + E85) (See: Powertrain Management/Computers and
Control Systems/Fuel Tank Pressure Sensor/Service and Repair/Fuel Tank Pressure Sensor Replacement (1500 SWB - 98.4L (26 Gal) Tank + E85)
)
P0461
DTC P0461
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 P0461
- Fuel Level Sensor 1 Performance
Diagnostic Fault Information
Circuit/System Description
The fuel level sensor changes resistance in response to the fuel level. The engine control module (ECM) monitors the signal circuit of the 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 tank is full, the sensor resistance is low and the ECM senses a low signal voltage. When the fuel tank is empty, the sensor resistance
is high and the ECM senses a high signal voltage. The ECM uses the signal circuit of the 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.
