Chevy

Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP

Ask an Expert,
Get an Answer ASAP!

Chevy
This answer was rated:

I get code PO446 Evap emission control system

I have a code PO446...
I have a code PO446 Evap emission control system vent circuit malf, this is on my 04 GMC 2500hd with 6.0L. What is the cause of this and how do you repair it ?
Show More
Show Less
Ask Your Own Chevy Question
Answered in 2 hours by:
7/25/2008
Bob
Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4,087
Experience: Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
Verified

This code refers to a problem with the evaporation system on your truck. GM has issued a technical bulletin on it for repairs. I will post a copy of it for you. Thanks

#02-06-04-037D: DTC P0446 (Restricted/Blocked Evap Vent Path) Set, Check Engine Light On (Replace Evaporative Emission (EVAP) Vent Valve Solenoid Assembly and Add/Relocate Filter Box Using Service Kit) - (Apr 16, 2008)

Subject:DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Check Engine Light On (Replace Evaporative Emission (EVAP) Vent Valve Solenoid Assembly and Add/Relocate Filter Box Using Service Kit)
Models:1999-2007 Chevrolet Silverado (Classic) Models
1999-2007 GMC Sierra (Classic) Models
2007-2008 Chevrolet Silverado Models
2007-2008 GMC Sierra Models

 


This bulletin is being revised to add new style pickups to the models and update the correction information to include a new location for the filter box. Please discard Corporate Bulletin Number 02-06-04-037C (Section 06 -- Engine/Propulsion System).


 

Condition

Some customers whose vehicles are operated in dusty type environments, such as farming or mining off-road type applications, may comment about the illumination of the check engine light, with a DTC of P0446 (Restricted/Blocked EVAP Vent Path) being set.

Cause

Dirt and dust intrusion into the EVAP canister vent hose assembly, resulting in restricted air flow, may cause this condition.

Correction (1999-2007 Classic/Old Style Models)

After following the published SI diagnostics for P0446 and determining that the EVAP canister vent valve is the cause of the MIL light, replace the existing EVAP canister vent valve assembly with a new assembly. This new assembly is a sealed unit that is designed to be vented through a remote filter box. To ensure correct installation, follow the procedures below.

1999-2003 Model Year (Use Service Kit P/N 19152345)

  1. Raise the vehicle. Suitably support the vehicle.
  2. Disconnect the EVAP canister vent valve electrical connector, if equipped.
  3. Disengage the two vent valve pipe clips securing the pipe to the underbody. Remove the clips from the underbody and discard.
  4. Disconnect the vent valve pipe at the EVAP canister.
  5. Remove and retain the EVAP canister vent valve bracket mounting bolt.
  6. Remove the complete EVAP canister vent valve assembly with bracket attached and discard.

    Important: The new canister vent valve will be installed in a new location, outside of the frame.

  7. Position and secure the new valve assembly to the frame bracket on the outside of the frame using the existing hole and mounting bolt.

    Tighten
    Tighten the bracket mounting bolt to 12 N·m (106 lb in).

  8. Connect the vent valve pipe to the EVAP canister.
  9. Install the two vent valve pipe clips into the existing underbody holes.
  10. Connect the EVAP canister vent valve electrical connector, if equipped.
  11. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission.
  12. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
  13. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
  14. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
  15. Raise the transmission and reinstall the transmission support.
  16. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
  17. Lower the vehicle.

2004-2007 Model Year (Use Service Kit P/N 19152349)

  1. Raise the vehicle. Suitably support the vehicle.
  2. Disconnect the EVAP canister vent valve electrical connector.
  3. Disconnect the canister pipe from the vent valve.
  4. Push in the retainer and remove the existing canister vent valve from the fuel tank clip or mounting bracket. Discard the old valve.
  5. Cut back the existing canister pipe approximately 51 mm (2 in) to remove the quick connect end.
  6. Install the new canister vent valve to the fuel tank clip or mounting bracket.
  7. Cut bulk 5/8" heater hose to a length of approximately 76 mm (3 in). Install the hose between the vent valve and the canister pipe and secure using clamps.
  8. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the area above the transmission.
  9. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
  10. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
  11. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
  12. Raise the transmission and reinstall the transmission support.
  13. Connect the EVAP canister vent valve electrical connector.
  14. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
  15. Lower the vehicle.

 

Correction (2007-2008 New Style Models)

After following the published SI diagnostics for P0446 and determining that the EVAP canister vent valve is the cause of the MIL light, replace the EVAP canister vent valve assembly and relocate the remote filter box. To ensure correct installation, follow the procedures below.

Use Service Kit P/N 19152349

  1. Raise the vehicle. Suitably support the vehicle.
  2. Disconnect the EVAP canister vent valve electrical connector.
  3. Disconnect the vent valve pipe quick connect from the canister.
  4. Either cut the existing valve vent pipe and leave the remaining section of pipe in the vehicle or remove along with the valve.
  5. Push in the retainer and remove the existing canister vent valve from the fuel tank clip or mounting bracket.
  6. Cut back the existing canister pipe approximately 51 mm (2 in) and retain the pipe for use with new valve.
  7. Connect the canister pipe quick connect to the canister.
  8. Install the new canister vent valve to the fuel tank clip or mounting bracket.
  9. Cut bulk 5/8" heater hose to a length of approximately 76 mm (3 in). Install the hose between the vent valve and the canister pipe and secure using clamps.
  10. Attach bulk 5/8" heater hose to the vent valve port and secure using a clamp. Run a length as needed along the frame rail routing to the passenger side area above the transmission.
  11. Cut the hose to determined length and install the supplied filter box. Secure using a clamp.
  12. Remove the transmission heat shield, if necessary.
  13. Remove the transmission support and lower the transmission assembly as necessary to allow for access to the new filter box location.
  14. Secure the filter box to the transmission vent hose just forward of the hose tee-section using a tie strap. DO NOT pinch or restrict the transmission vent hose. The filter box opening should be pointing downward.
  15. Raise the transmission and reinstall the transmission support.
  16. Reinstall the transmission heat shield.
  17. Connect the EVAP canister vent valve electrical connector.
  18. Tie strap the hose as needed along the frame rail in order to keep the hose away from pinch-points and heat sources.
  19. Lower the vehicle.

 

Parts Information

Part Number

Description

Qty

Material Allowance

19152345 (1999-2003 Model Year)

Solenoid Kit, EVAP Emission Canister Vent Valve

1

--

19152349 (2004-2008 Model Year)

Solenoid Kit, EVAP Emission Canister Vent Valve

1

--

(###) ###-####(5/8" X 25' roll)

Hose

Cut to Length

$10.80 USD ($22.59 CAD)

12337820 (10 per pack)

Tie-Strap

5

$3.80 USD ($4.55 CAD)

15620999 (10 per pack)

Clamp

2 (1999-2003)

or

4 (2004-2008)

$3.78 USD ($7.08 CAD) (1999-2003)

or

$7.56 USD ($14.17 CAD) (2004-2008)

Bob
Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4,087
Experience: Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)
Verified
Bob and 87 other Chevy Specialists are ready to help you
Ask your own question now
Ask Bob Your Own Question
Bob
Bob
Bob, Auto Tech
Category: Chevy
Satisfied Customers: 4,087
4,087 Satisfied Customers
Experience: Plus 40 years GM, over 30 certified with Chevrolet, ASE certified Master Tech. (Expired, Retired)

Bob is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money.

Todd LRochester NY

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

GM Tech (Cam)

GM Tech (Cam)

Chevy Technician

15,249 satisfied customers

GM Grand Master Technician 2007. 14 years experience.

Gary

Gary

Chevy Technician

9,196 satisfied customers

15 years GM master tech

Tim&#039;s Auto Repair

Tim's Auto Repair

mechanic

8,847 satisfied customers

Have owned a repair shop for 25 yrs.

Dave Nova

Dave Nova

Chevrolet Technician

7,092 satisfied customers

ASE Master Certification. GM World Class Certification

John

John

Master A.S.E Automotive technician

4,071 satisfied customers

A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician

Don - Mo Lurch

Don - Mo Lurch

Auto Mech / Electronics

2,900 satisfied customers

Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.

Ron Z.

Ron Z.

- Chevy Tech -

2,682 satisfied customers

18+yrs experience. State Inspector and Chevy Diagnostics

< Previous | Next >

Related Chevy Questions
The speedometer stopped working, the transmission will not
the speedometer stopped working, the transmission will not shiftout of low, the brake abs light is on and the brake trouble light is also on … read more
Gary
Gary
Chevy Technician
Vocational, Technical or Trade Scho
9,196 satisfied customers
Driver door lock and unlocks with key fob and door panel
Driver door lock and unlocks with key fob and door panel switch. Rear lift gate door works too. All other passengers do not work. Vehicle is a 2017 Suburban HD.… read more
Todd M
Todd M
Owner
ASE Certification
1,293 satisfied customers
Skiping ruof idel smom times quik,s @when stop changed fuel
skiping ruof idel smom times quik,s @when stop changed fuel fitter and spark plugs 20005 chevey cobalt some times runs good … read more
Tim&#039;s Auto Repair
Tim's Auto Repair
mechanic
High School or GED
8,847 satisfied customers
It's a piece of shit. 2012 Chevy Malibu LT. Well I checked
Well I checked the codes and it hit for bothering crankshaft sensors so I replaced them then I cleared the code and the check engine light came back on with same crankshaft codes … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
My radiator house came off of were it attached to the
My radiator house came off of were it attached to the thermostat. I replaced the thermostat added anti-freeze. Then I tried to start it an more it want start. What can be the problem? … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
Has spark but on fuel to carb. No gas hog but was starting
no gas hog but was starting hard had to pump a bunch till started but no fire … read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
Getting a #1 cylendar misfiring code and wondering what the
getting a #1 cylendar misfiring code and wondering what the ideal PSI range should be on a chevy 5.3 liter engine? … read more
Ron Z.
Ron Z.
- Chevy Tech -
Vocational, Technical or Trade Scho
2,682 satisfied customers
Dealership wanted to replace engine. 2010 Chevy Silverado
Dealership wanted to replace engine. 2010 Chevy Silverado 5.3L engine but husband decided on oil pump and mechanic pressure checked oil pick-up tube which he discovered had several leaks around connec… read more
Gary
Gary
Chevy Technician
Vocational, Technical or Trade Scho
9,196 satisfied customers
I have a 2002 suburban have a code of p0178 on the flex fuel
hi I have a 2002 suburban have a code of p0178 on the flex fuel sensor I have 5.3 to 5.5 volts on the white wire pink 0 black seems to be ground … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
25 satisfied customers
I'm trying to find the passenger lock relay(s) on 2017
I'm trying to find the passenger lock relay(s) on 2017 Suburban HD … read more
nelson freitas
nelson freitas
Automotive Technician
Vocational, Technical or Trade School
83 satisfied customers
It is showing a p069e code. This all started after putting
It is showing a p069e code. This all started after putting on a magnaflow cat back exhaust system. … read more
Todd M
Todd M
Owner
ASE Certification
1,293 satisfied customers
Getting codes 24c4 and 2493. P24c4 and 2493 reset and came
Getting codes 24c4 and 2493 JA: Just to clarify, what's the exact code? And have you tried to reset it? Customer: P24c4 and 2493 reset and came back on JA: What is the model/year of your Chevy? Custom… read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
When I start the engine, the power steering automatically
when I start the engine, the power steering automatically forces the wheels all the way to the left. They are then locked there and I can't move them. … read more
Jaybird61
Jaybird61
Master Automotive Mechanic
1,900 satisfied customers
2007 chevy Silverado ac is blowing hot air on both sides. It
2007 chevy Silverado ac is blowing hot air on both sides. It does this at random, put sometime when I hit a dump? … read more
Pete
Pete
Independent Auto Technician
Vocational, Technical or Trade Scho
138 satisfied customers
Have '97 s-10 that had fuel pump replaced, now gauge reads
have '97 s-10 that had fuel pump replaced, now gauge reads 'empty' all the time. trying to locate 4 pin (2x2) fuel pump connector so i can check continuity from sender signal to sender return. … read more
AMEDEE
AMEDEE
AUTOMOTIVE TECHNICIAN
Vocational, Technical or Trade Scho
9,105 satisfied customers
This is a story: I purchased a 2012 Chevy 2500HD LML about 6
This is a long story: I purchased a 2012 Chevy 2500HD LML about 6 months ago. one day it popped a bunch of DTCs including NOx Sensor 2 and P20EE/P2BAD. Because the DEF tank was caked with ammonia depo… read more
Chris (aka - Moose)
Chris (aka - Moose)
Vocational, Technical or Trade Scho
108 satisfied customers
1999 chevy Tahoe 4x4 5.7l turned blower switch on and all
1999 chevy Tahoe 4x4 5.7l turned blower switch on and all sorts of electrical functions went out. power windows, 4wd won't engage, windshield wipers, blinkers but left on dash stays dimly lit, headlig… read more
AMEDEE
AMEDEE
AUTOMOTIVE TECHNICIAN
Vocational, Technical or Trade Scho
9,105 satisfied customers
My Chevy is overheating. It start and runs fine but then
My Chevy is overheating. It start and runs fine but then runs hot. All of a sudden, then, it will give a little surge and then the temp will drop quickly. On an older Chevy, I would suspect the thermo… read more
Mechanic01
Mechanic01
1,160 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x