Damm Evap Code 0446

[bigblue113]

hey all...new member first post...iv been researching here for awhile now about this damm code...i had two codes pop up cat code 0449 and 0446...like many i started throwing parts at her....heres what i started with first new vent solinoide for an 06 suburban..was round insted of square but got it to work..no go..then the intake solinoide..no go...the bank 1 02 sensor..no go..then replaced the cats that were only 3 years old..got the cat code to go away...still got the evap code..took down the charcol canister and had some oil/gas come out of the smaller line i believe that runs to the gas tank..blew air threw all lines and the charcol box...some charcol dust blew out but not much dirt..and it felt kinda heavy...but i never fill my tank...im ready to drive it into a lake....im past inspection with a red sticker for oct..i have no pressure in the tank...i only know this by opening the cap and not hearing and pressure release...the truck runs great..with 124,000 miles on her..03 silverado 4x4 extended cab long bed....i hate to keep guessing but can not afford to take it to the dealer...im thinking now it may be the pressure sensor ontop of the fuel tank....any insight would be very greatful....

[dlewis1111]

hey all...new member first post...iv been researching here for awhile now about this damm code...i had two codes pop up cat code 0449 and 0446...like many i started throwing parts at her....heres what i started with first new vent solinoide for an 06 suburban..was round insted of square but got it to work..no go..then the intake solinoide..no go...the bank 1 02 sensor..no go..then replaced the cats that were only 3 years old..got the cat code to go away...still got the evap code..took down the charcol canister and had some oil/gas come out of the smaller line i believe that runs to the gas tank..blew air threw all lines and the charcol box...some charcol dust blew out but not much dirt..and it felt kinda heavy...but i never fill my tank...im ready to drive it into a lake....im past inspection with a red sticker for oct..i have no pressure in the tank...i only know this by opening the cap and not hearing and pressure release...the truck runs great..with 124,000 miles on her..03 silverado 4x4 extended cab long bed....i hate to keep guessing but can not afford to take it to the dealer...im thinking now it may be the pressure sensor ontop of the fuel tank....any insight would be very greatful....

 

Had similar problems with my 08, and the dealer replaced the vent solenoid twice with same codes coming back. It turned out to be a faulty gas cap.......

[bigblue113]

yes..but doesnt a bad gas cap throw a diffrent code other then an evap code?...like a leak in the system code??

[dlewis1111]

yes..but doesnt a bad gas cap throw a diffrent code other then an evap code?...like a leak in the system code??

 

not sure, was under warranty and dealer took care of it. was just sharing my experience.

[bigblue113]

well thanks for sharing......i may try that...but still waiting for more replys/info..here...

[bigblue113]

is there a fuse to this system???,...anyone???

[jrrod2004]

is there a fuse to this system???,...anyone???

 

 

Nope. No fuse on that system...this should help:

 

 

 

 

2003 Chevrolet Chevy K Silverado - 4WD | Sierra, Silverado (VIN C/K) Service Manual | Document ID: 846466

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 Open and the EVAP canister vent

solenoid 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 Closed

and the EVAP canister vent solenoid 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 following table illustrates the relationship between the ON and OFF states, and the Open or

Closed states of the EVAP canister purge and vent valves.

Conditions for Running the DTC

Conditions for Setting the DTC

Action Taken When the DTC Sets

Control Module

Command

EVAP Canister Purge

Solenoid

EVAP Canister Vent

Solenoid

ON Open Closed

OFF Closed Open

• DTC P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0121, P0122,

P0123, P0125, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0147,

P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0167, P0220, P0442,

P0443, P0449, P0452, P0453, P0455, P0502, P0503, P1111, P1112, P1114, P1115, P1120

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 startup engine coolant temperature (ECT) is between 4-30°C (39-86°F).

• The startup 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 fuel tank pressure sensor is less than -10 inches H2O.

• The above condition is present for more than 30 seconds.

• 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 © 2010 General Motors Corporation. All rights reserved.

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Conditions for Clearing the MIL/DTC

Diagnostic Aids

Test Description

The number below refers to the step number on the diagnostic table.

3. This test determines if the failure is present or intermittent.

operating conditions to the Freeze Frame and updates the Failure Records.

• 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.

• An intermittent condition could be caused by a damaged evaporative emission (EVAP) vent

housing, a temporary blockage at the EVAP vent solenoid 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

Step Action Values Yes No

Schematic Reference: Emission Hose Routing Diagram

1

Did you perform the Diagnostic System

Check-Engine Controls?

--

Go to Step 2

Go to

Diagnostic

System Check

- Engine

Controls

2

Inspect the evaporative emission (EVAP)

system for the following conditions:

Did you find and correct the condition?

• A damaged EVAP vent solenoid--Refer

to Evaporative Emission Canister Vent

Solenoid Valve Replacement .

• A pinched EVAP vent hose

• A damaged EVAP canister--Refer to

Evaporative Emission Canister

Replacement .

--

Go to Step 15 Go to Step 3

3

1. Turn OFF the ignition.

2. Disconnect the purge line from the

EVAP purge solenoid. Refer to

Evaporative Emission Canister Purge

Solenoid Valve Replacement .

-1 to

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3. Turn ON the ignition, with the engine

OFF.

Is the fuel tank pressure sensor parameter

within the specified range?

+1 in H2O

Go to Step 4 Go to Step 9

4

Important: DO NOT exceed the specified

value in this step. Exceeding the specified

value may produce incorrect test results.

1. Turn OFF the ignition.

2. Connect the EVAP purge pipe.

3. Connect the J 41413-200 Evaporative

Emissions System Tester (EEST)

power supply clips to a known good

12-volt source.

4. Install the J 41415-40 Fuel Tank Cap

Adapter to the fuel fill pipe.

5. Connect the fuel fill cap to the J

41415-40 .

6. Connect the J 41413-200

nitrogen/smoke supply hose to the J

41415-40 .

7. Turn ON the ignition, with the engine

OFF

8. Command the EVAP vent solenoid

closed with a scan tool.

9. Turn the nitrogen/smoke valve on

theJ 41413-200 control panel to

NITROGEN.

10. Use the remote switch to pressurize

the EVAP system to the first specified

value.

11. Observe the fuel tank pressure sensor

in H2O with a scan tool.

12. Command the EVAP vent solenoid

open with a scan tool.

Is the fuel tank pressure sensor parameter

less than the second specified value?

5 in H2O

1 in H2O

Go to Step 5 Go to Step 7

5

1. Connect the nitrogen/smoke hose to

the EVAP service port.

2. Remove the J 41415-40 .

3. Install the fuel fill cap to the fuel fill

pipe.

4. Start the engine.

5. Allow the engine to idle.

6. Use the purge/seal function to seal

the system, with a scan tool.

7. Command the EVAP canister purge

solenoid valve to 30 percent.

8. Observe the vacuum/pressure gage of

the J 41413-200 until it reaches

approximately 16 in H2O.

9. Use the purge/seal function to seal

1 in H2O

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the system, with a scan tool.

Is the FTP parameter on a scan tool within

the specified value of the vacuum/pressure

gage on the J 41413-200 , until the vacuum

reached the abort limit on a scan tool? Go to Step 6 Go to Step 9

6

Did the FTP parameter on a scan tool

display more than the specified value?

3.2 V

Go to

Diagnostic

Aids Go to Step 9

7

Disconnect the EVAP vent hose from the

EVAP vent solenoid.

Is the fuel tank pressure sensor parameter

less than the specified value?

1 in H2O

Go to Step 13 Go to Step 8

8

Disconnect the EVAP vent hose from the

EVAP canister.

Is the fuel tank pressure sensor parameter

less than the specified value?

1 in H2O

Go to Step 11 Go to Step 14

9

Test the low reference circuit of the FTP

sensor for an open or high resistance. Refer

to Circuit Testing and Wiring Repairs in

Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15 Go to Step 10

10

Test for poor connections at the harness

connector of the fuel tank pressure (FTP)

sensor. Refer to Testing for Intermittent

Conditions and Poor Connections and

Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15 Go to Step 12

11

Repair the pinched or restricted EVAP vent

hose.

Did you complete the repair?

--

Go to Step 15 --

12

Replace the FTP sensor. Refer to Fuel Tank

Pressure Sensor Replacement .

Did you complete the replacement?

--

Go to Step 15 --

13

Replace the EVAP vent solenoid. Refer to

Evaporative Emission Canister Vent

Solenoid Valve Replacement .

Did you complete the replacement?

--

Go to Step 15 --

14

Replace the EVAP canister. Refer to

Evaporative Emission Canister

Replacement .

Did you complete the replacement?

--

Go to Step 15 --

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15

1. Turn OFF the ignition.

2. Disconnect the purge line from the

EVAP purge solenoid. Refer to

Evaporative Emission Canister Purge

Solenoid Valve Replacement .

3. Turn ON the ignition, with the engine

OFF.

Is the fuel tank pressure sensor parameter

within the specified range?

-1 to +

1 in H2O

Go to Step 16 Go to Step 2

16

Important: DO NOT exceed the specified

value in this step. Exceeding the specified

value may produce incorrect test results.

1. Turn OFF the ignition.

2. Reconnect all disconnected

components.

3. Connect the J 41413-200 to the fuel

fill pipe.

4. Turn ON the ignition, with the engine

OFF

5. Command the EVAP vent solenoid

closed with a scan tool.

6. Turn the nitrogen/smoke valve on

theJ 41413-200 control panel to

NITROGEN.

7. Use the remote switch to pressurize

the EVAP system to the first specified

value.

8. Observe the fuel tank pressure sensor

in H2O with a scan tool.

9. Command the EVAP vent solenoid

open with a scan tool.

Is the fuel tank pressure sensor parameter

less than the second specified value?

5 in H2O

1 in H2O

Go to Step 17 Go to Step 2

17

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been

diagnosed?

--

Go to

Diagnostic

Trouble Code

(DTC) List System OK

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[bigblue113]

thank you...now in english if u please......no really.. i saw that post before somewhere else...and i do gather that this is the way to properley test the evap system....unfortunetley i do not have the expertise nor the hardware to do this diagnostic test...im assuming you work at a dealership and like so many of you dealership guys who look down on us diyers so to speak rub it in our faces with your so called copy and paste procedures and so on..and im sure most deaerlships only have one out of 10 mechanics that could run this equipment and understand it....so im sure you knew this when you copyed and pasted this...thanks ...really i should print that out and use it for tp....because without the tens of thousands of dollars worth of equipment like only dealers have and a few good shops thats all its good for.......

[txab]

thank you...now in english if u please......no really.. i saw that post before somewhere else...and i do gather that this is the way to properley test the evap system....unfortunetley i do not have the expertise nor the hardware to do this diagnostic test...im assuming you work at a dealership and like so many of you dealership guys who look down on us diyers so to speak rub it in our faces with your so called copy and paste procedures and so on..and im sure most deaerlships only have one out of 10 mechanics that could run this equipment and understand it....so im sure you knew this when you copyed and pasted this...thanks ...really i should print that out and use it for tp....because without the tens of thousands of dollars worth of equipment like only dealers have and a few good shops thats all its good for.......

Hmmm.... Let me say your way off base about M. Cueva. With your attitude why would someone want to help you? I'll see if I can dig out a "See Spot Fix the Truck" book for you. Maybe with the large print and small words you can get through it and comprehend it

 

The procedure posted above is how you diagnose the problem . If you don't have the tools or ability to do it, then take to someone who does. Safe up your money, or just keep throwing parts it.

 

Enjoy your new TP.

 

Don't know how much searching or reading you've done here on the sight but here are somethings to look over:

 

http://www.google.com/search?q=p0446+site%...amp;safe=images

 

http://www.google.com/search?q=p0446+site%...964acb7c7145c5b

[bigblue113]

thanks ...i will......and honestley....thow the info was correct...come on now..how many really understand that???...do u?...so to is useless

[jrrod2004]

thanks ...i will......and honestley....thow the info was correct...come on now..how many really understand that???...do u?...so to is useless

 

 

Dude, not a dealership employee. that kinda pisses me off with that tone. I had the same problem as you and I got it fixed with the remote filter kit and the changing of the vent valve. I would replace the vent valve and relocate the filter to the engine bay. Check your gas cap and make sure that the Evap Purge Valve is also working. common issue

 

Point blank, I give the technical data that I have available to me for the benefit of others that have either been 1) screwed by the dealership 2) have no idea what is going on with a particular code or 3) would like to read some useful info.

 

My profession: Liability Claims Adjuster for auto insurance. I used to work for GM corporate and was the guy that told you that I got your back or to piss off for warranty work. Never was a dealership employee and I got more respect for dealership employees as they have it harder than us.

 

in the words of Snake Doctor: "Have a Good One"

[bigblue113]

y is it guys get ruffled so easley....?...lol....look i appriciate you reply thankyou....i just can help it i guess..it must be the north in me..lol.. ...no its just me venting and being frustraded with the truck and countless hours researching....look flat out sorry for coming acrossed areigant...no worries..i replaced alot....but still doesnt add up to the cost a dealer would charge just to look at it...cats were 400,,,but warranty by the seller covered replacement....my gut is telling me that its the pressure sensor ontop of the fuel tank....cause i have no blockage....replaced both solinoids...only things left are the charcoal canister and the pressure valve...and again i have no pressure in the tank...when i take the cap off after i travel some distance there is no sound of a pressure release....none whats so ever and a bad gas cap throws a leak code......so this is y now after all the new parts to the system this has to be it....right??...lol....ill geter done sooner or later...

[wfleeger]

 

[jrrod2004]

y is it guys get ruffled so easley....?...lol....look i appriciate you reply thankyou....i just can help it i guess..it must be the north in me..lol.. ...no its just me venting and being frustraded with the truck and countless hours researching....look flat out sorry for coming acrossed areigant...no worries..i replaced alot....but still doesnt add up to the cost a dealer would charge just to look at it...cats were 400,,,but warranty by the seller covered replacement....my gut is telling me that its the pressure sensor ontop of the fuel tank....cause i have no blockage....replaced both solinoids...only things left are the charcoal canister and the pressure valve...and again i have no pressure in the tank...when i take the cap off after i travel some distance there is no sound of a pressure release....none whats so ever and a bad gas cap throws a leak code......so this is y now after all the new parts to the system this has to be it....right??...lol....ill geter done sooner or later...

 

 

If you call that north, then your bite needs some fine tuning

 

Did you clear the code by chance each time a component was replaced?

[jrrod2004]

 

where is the beer tony? you got the popcorn, now where is the beer