Cobalt 2006-2008, G5 2007

2.2L L4 VIN F Auto 5

Print

Trouble Code: P0442



Evaporative Emission (EVAP) System Small Leak Detected

Possible Causes:



Damaged EVAP purge solenoid
 
Damaged EVAP vent valve or EVAP canister
 
Incorrectly routed, kinked, or damaged EVAP pipes and hoses
 

Trouble Code: P0443



Evaporative Emission (EVAP) Purge Solenoid Control Circuit

Trouble Code: P0443



EVAP Purge Solenoid Control Circuit Malfunction

Possible Causes:



Purge solenoid control circuit is open or shorted to ground
 
Purge solenoid control circuit is shorted to system power (B+)
 
Purge solenoid power circuit is open (test the IGN1 fuse)
 
Purge solenoid is damaged or has failed
 
ECM has failed
 

Trouble Code: P0446



Evaporative Emissions (EVAP) Vent System Performance

Possible Causes:



The EVAP system tests run when the engine is first started and meets the Conditions for Running the DTC. An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill condition.
 
An EVAP canister, vent hose, or vent solenoid valve that has restricted flow may cause this DTC to set. Using a purge solenoid command with a scan tool will allow vacuum to be applied to the system instead of pressure. With the engine running, the EVAP canister vent solenoid valve open, and the EVAP canister purge solenoid valve commanded to 100 percent, the fuel tank vacuum should not increase to more than 5 inches H2O.
 
An EVAP canister filter that is restricted can cause this DTC to set. Refer to Evaporative Emission (EVAP) System Cleaning .
 
Disconnecting one component at a time while the EVAP system is under flow will help to pinpoint a restriction in the system.
 
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
 
For intermittent conditions, refer to Intermittent Conditions .
 

Trouble Code: P0446



Evaporative Emission (EVAP) Vent System Performance

Possible Causes:



An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent solenoid valve inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill condition.
 
An EVAP canister filter that is restricted can cause this DTC to set. Refer to Evaporative Emission System Cleaning .
 

Trouble Code: P0446



Evaporative Emissions (EVAP) Vent System Performance

Possible Causes:



EVAP vent fresh air hose is clogged, kinked or restricted
 
EVAP Vent solenoid is contaminated, damaged or has failed
 
FTP sensor is out-of-calibration, damaged or "skewed"
 
ECM has failed
 

Trouble Code: P0449



Evaporative Emission (EVAP) Vent Solenoid Control Circuit

Trouble Code: P0449



EVAP Vent Solenoid Control Circuit Malfunction

Possible Causes:



Vent solenoid control circuit is open or shorted to ground
 
Vent solenoid control circuit is shorted to system power (B+)
 
Vent solenoid power circuit is open (test the ENG1 fuse)
 
Vent solenoid is damaged or has failed
 
ECM has failed
 

Trouble Code: P0451



Fuel Tank Pressure (FTP) Sensor Performance

Possible Causes:



A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
 
By using the purge solenoid command on a scan tool, vacuum can be applied to the system instead of pressure. With the EVAP canister vent solenoid valve open and the EVAP canister purge solenoid valve commanded to 100 percent, the vacuum should not increase to more than 6 inches H2O.
 
An EVAP canister filter that is restricted can cause this DTC to set.
 
Ensure that the reference port on the FTP sensor is unobstructed.
 

Trouble Code: P0451



Fuel Tank Pressure (FTP) Sensor Performance

Possible Causes:

P0451 and P0454



A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
 
Ensure that the reference port on the FTP sensor is unobstructed.
 
An FTP sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 while taking a snapshot.
 

Trouble Code: P0451



Fuel Tank Pressure (FTP) Sensor Performance

Possible Causes:



EVAP purge solenoid valve
 
FTP sensor
 
EVAP canister vent solenoid valve and vent pipe for a blockage or restriction
 

Trouble Code: P0452



Fuel Tank Pressure Sensor Circuit Low Input

Possible Causes:



The rear body pass-through connector may be a convenient point for testing.
 

Trouble Code: P0452



Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

Possible Causes:

P0451 and P0454



A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
 
Ensure that the reference port on the FTP sensor is unobstructed.
 
An FTP sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 while taking a snapshot.
 

Trouble Code: P0453



Fuel Tank Pressure (FTP) Sensor Circuit Voltage

Trouble Code: P0453



Fuel Tank Pressure (FTP) Sensor Circuit High Voltage

Possible Causes:

P0451 and P0454



A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
 
Ensure that the reference port on the FTP sensor is unobstructed.
 
An FTP sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 while taking a snapshot.
 

Trouble Code: P0454



Fuel Tank Pressure (FTP) Sensor Circuit Intermittent

Possible Causes:



This diagnostic is designed to detect an unexpected abrupt voltage signal change from the FTP.
 
Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To look at the sensor signal under vacuum conditions, use snapshot and the purge/seal function to capture data while commanding purge to 30 percent, and then plot the data to look for erratic sensor operation. A similar inspection can be done for the pressure side of the sensor range by applying pressure with the J 41413-200 Evaporative Emissions System Tester (EEST) while taking a snapshot.
 
Ensure that the reference port on the FTP sensor is unobstructed.
 

Trouble Code: P0454



Fuel Tank Pressure (FTP) Sensor Intermittent

Possible Causes:

P0451 and P0454



A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
 
Ensure that the reference port on the FTP sensor is unobstructed.
 
An FTP sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 while taking a snapshot.
 

Trouble Code: P0454



Evaporative Emission (EVAP) System Large Leak Detected

Possible Causes:



Inspect for a damaged fuel filler neck seal surface.
 
Blockage or restriction in the EVAP purge solenoid valve, purge pipe, EVAP canister, or vapor pipe,
 
Inspect for a loose, missing, damaged, or incorrect fuel fill cap
 
FTP sensor has failed
 

Trouble Code: P0455



Evaporative Emission (EVAP) System Large Leak

Possible Causes:



A loose, missing, incorrect, or damaged fuel fill cap may cause this DTC to set.
 
A leak in the EVAP system can be verified by the use of a flow meter on the J 41413-200 Evaporative Emissions System Tester (EEST). Refer to the J 41413-200 operation manual for flow meter use.
 
To help locate intermittent leaks, use the J 41413-200 to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. Introducing smoke in 15-second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
 
A temporary blockage in the EVAP canister purge solenoid valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
 
To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
 
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
 
For intermittent conditions, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P0455



Evaporative Emission (EVAP) System Large Leak

Possible Causes:



A loose, missing, incorrect, or damaged fuel fill cap may cause this DTC to set.
 
To help locate intermittent leaks, use the J 41413-200 to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT . Introducing smoke in 15-second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
 
To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
 
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.
 
A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool Purge/Seal function to create a vacuum, seal the system and observe the FTP parameter for the vacuum decay, this type of leak may be detected.
 
If a small leak is difficult to find, it may be necessary to remove the EVAP components and leak test them one at a time.
 

Trouble Code: P0455



Evaporative Emissions (EVAP) System Very Small Leak Detected

Possible Causes:



Damaged EVAP purge solenoid
 
Damaged EVAP vent valve or EVAP canister
 
Incorrectly routed, kinked, or damaged EVAP pipes and hoses
 

Trouble Code: P0456



Evaporative Emission (EVAP) Purge Solenoid Control Circuit Low Voltage

Possible Causes:



EVAP purge solenoid control circuit for a shorted to ground.
 
EVAP purge solenoid shorted to voltage or an open/high resistance
 
Faulty EVAP purge solenoid.
 
ECM has failed
 

Trouble Code: P0458



Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage

Possible Causes:



EVAP purge solenoid control circuit for a shorted to ground.
 
EVAP purge solenoid shorted to voltage or an open/high resistance
 
Faulty EVAP purge solenoid.
 
ECM has failed
 

Trouble Code: P0459



Fuel Level Sensor High Input

Possible Causes:



Fuel level sensor signal circuit is shorted to system power
 
Fuel level sensor ground circuit is open
 
Fuel level sender is damaged, binding or not aligned properly
 
ECM has failed
 

Trouble Code: P0461



Fuel Level Sensor Performance

Possible Causes:



Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same Freeze Frame conditions, i.e. RPM, engine load, vehicle speed, temperature, etc. This will isolate when the DTC failed. Refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P0461



Fuel Level Sensor Circuit Performance

Trouble Code: P0462



Fuel Level Sensor Circuit Low Voltage

Possible Causes:



Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same Freeze Frame conditions, i.e. RPM, engine load, vehicle speed, temperature, etc. This will isolate when the DTC failed. Refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P0462



Fuel Level Sensor Circuit Low Voltage

Trouble Code: P0463



Fuel Level Sensor Circuit High Voltage

Possible Causes:



Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same Freeze Frame conditions, i.e. RPM, load, vehicle speed, temperature, etc. This will isolate when the DTC failed. Refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P0463



Fuel Level Sensor Circuit High Voltage

Trouble Code: P0464



Fuel Level Sensor Circuit Intermittent

Possible Causes:



Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the vehicle within the same freeze frame conditions, i.e. RPM, engine load, vehicle speed, temperature, etc. This will isolate when the DTC failed.
 
Refer to Testing for Intermittent Conditions and Poor Connections .
 
If the DTC sets without a refueling event, refer to Fuel Gage Inaccurate or Inoperative .
 

Trouble Code: P0464



Fuel Level Sensor 1 Circuit Intermittent

Trouble Code: P0480



Cooling Fan Relay 1 Control Circuit Malfunction

Possible Causes:



If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections .
 
Review the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.
 

Trouble Code: P0480



Cooling Fan Relay 1 Control Circuit

Trouble Code: P0481



Cooling Fan Relay 2 Control Circuit Malfunction

Possible Causes:



If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections .
 
Review the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.
 

Trouble Code: P0481



Cooling Fan Relay 2 Control Circuit

Trouble Code: P0482



Cooling Fan Relay 3 Control Circuit Malfunction

Possible Causes:



If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections .
 
Review the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.
 

Trouble Code: P0496



Evaporative Emission (EVAP) System Flow During Non-Purge

Possible Causes:



An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge solenoid valve or an EVAP canister purge solenoid valve that is temporarily stuck open
 
For intermittent conditions, refer to Testing for Intermittent Conditions and Poor Connections .
 

Trouble Code: P0496



Evaporative Emission System Flow During Non-Purge

Trouble Code: P0496



Evaporative Emission (EVAP) System No Flow During Purge

Possible Causes:



Fuel filler cap is very loose, missing or the wrong part
 
Fuel tank, fuel filler neck or fuel sending unit 'O' ring is leaking
 
Fuel tank pressure sensor is damaged, disconnected or it failed
 
Fuel tank vapor line(s) is clogged, damaged or disconnected
 
Purge valve vapor line is clogged, damaged, or disconnected
 
Purge solenoid is not opening (it may be damaged or sticking)
 
Vent solenoid is not closing (it may be damaged or sticking)
 
ECM has failed
 

 
label.common.footer.alt.autozoneLogo