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AMEDEE
AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 21786
Experience:  ASE MASTER TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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2005 Chevy: V6..NJ emissions inspection for codes P0446 & P0455

Resolved Question:

2005 Chevy Equinox V6 failed NJ emissions inspection for codes P0446 & P0455. What do these codes mean? Is it a big job? Can any mechanic do the repair?
Submitted: 5 years ago.
Category: Chevy
Expert:  AMEDEE replied 5 years ago.

Hello!

 

These codes are evap codes. This is just a simple evap system malfunction. The correct fix is to have your evap system smoked tested for leaks. If none is found, there usually is a vent valve or a purge valve that is at fault causing these codes.

 

Here is the definitions for these codes.

 

DTC P0446

SYSTEM DESCRIPTION
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.




The table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:

DTC P0446 Evaporative Emission (EVAP) Vent System Performance

CONDITIONS FOR RUNNING THE DTC


Before the PCM can report DTC P0446 failed, DTCs P0442 and P0496 must run and pass.
DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0125, P0128, P0443, P0449, P0451, P0452, P0453, P0455, P0502, P1106, P1107, P1111, P1112, P1114, P1115, P1125, P1516, P2101, P2108, P2119, P2120, P2125, P2138 are not set.
The ignition voltage is between 10-18 volts .
The barometric pressure (BARO) is more than 75 kPa .
The fuel level is between 15-85 percent .
The engine coolant temperature (ECT) is between 4-30°C (39-86°F) .
The intake air temperature (IAT) is between 4-30°C (39-86°F) .
The Startup ECT and IAT are within 9°C (16°F) of each other.
The vehicle speed sensor (VSS) is less than 129 km/h (80 mph) .
DTC P0446 runs once per cold start when the above conditions are met.
ACTION TAKEN WHEN THE DTC SETS


The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC


The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS


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 problem.
For intermittent conditions, refer to Intermittent Conditions

p0455

DTC P0455

SYSTEM DESCRIPTION
The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP canister vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or if the vacuum level decreases too rapidly, this DTC sets.




The table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent solenoid valves.

DTC DESCRIPTORS
This diagnostic procedure supports the following DTC:

DTC P0455 Evaporative Emission (EVAP) System Large Leak Diagnostic

CONDITIONS FOR RUNNING THE DTC


Before the PCM can report DTC P0455 failed, DTC P0496 must run and pass.
DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0125, P0128, P0220, P0443, P0446, P0449, P0452, P0453, P0455, P0502, P1106, P1107, P1111, P1112, P1114, P1115, P1125, P1516, P2101, P2108, P2119, P2120, P2125, P2135, P2138 are not set.
The ignition voltage is between 10-18 volts .
The barometric pressure (BARO) is more than 75 kPa .
The fuel level is between 15-85 percent .
The engine coolant temperature (ECT) is between 4-30°C (39-86°F) .
The intake air temperature (IAT) is between 4-30°C (39-86°F) .
The Startup ECT and IAT are within 9°C (16°F) of each other.
The vehicle speed sensor (VSS) is less than 129 km/h (80 mph) .
DTC P0455 runs once per cold start when the above conditions are met.
CONDITIONS FOR SETTING THE DTC
The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.

ACTION TAKEN WHEN THE DTC SETS


The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC


The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS


To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) 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.

AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 21786
Experience: ASE MASTER TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
AMEDEE and 8 other Chevy Specialists are ready to help you
Customer: replied 5 years ago.
Your answer is quite detailed. Is this a one day job? Is it very expensive? Ballpark figure would be appreciated if possible. should I use A dealer or is a NJ state sanctioned emissions shop[ ok?
Expert:  AMEDEE replied 5 years ago.
You could use a dealer and even a emissions shop if they replace these kind of parts. You should be looking at no more than maybe a few hundred dollars parts ad labor. and yes, this is a one day job! Maybe even less!
AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 21786
Experience: ASE MASTER TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
AMEDEE and 8 other Chevy Specialists are ready to help you

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