Cause Of Catalyitc Converter Failure? Code 0446

dichdoc · July 9, 2007

2001 Yukon 5.3l developed rattle after much searching I traced it to the flattened cross over pipe coming from the drivers side going to passenger side. If you hit it with the heal of your hand it will replicate the sound with engine off. Exhaust system seemed to vibrate alot. while running. Had been fighting a trouble code of 0446 and had replaced the "valve" Would this cause a cat failure? We also live on a bad gravel road which clogs the valve could the wash board and pot holes cause the cat failure? Would a bad O2 sensor throw a code? We haven't noticed any real driveability issues either. Not wanting to ruin another cat. Thanks for the help TB

GMTRUCKTECH · July 10, 2007

Subject:LR4, LM4, LM7, L59, LQ9, LQ4, L18 DTC P0446 (Restricted/Blocked EVAP Vent Path) Set, Service Engine Soon (SES) Lamp Illuminated (Replace Vent Solenoid and Bracket) #04-06-04-055A - (03/20/2006)

Models:2000-2003 Cadillac Escalade

2002-2003 Cadillac Escalade EXT

2003 Cadillac Escalade ESV

2000-2003 Chevrolet Suburban, Tahoe

2002-2003 Chevrolet Avalanche

2000- 2003 GMC Yukon, Yukon XL

with 4.8L, 5.3L, 6.0L, 8.1L Vortec™ V8 Engine (VINs V, P, T, Z, N, U, G -- RPOs LR4, LM4, LM7, L59, LQ9, LQ4, L18)

This bulletin is being revised to add updated warranty information and enhance the content. Please discard Corporate Bulletin Number 04-06-04-055 (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 instrument panel SES light, with a DTC of P0446 (Restricted/Blocked EVAP Vent Path) being set.

Cause

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

Correction

DO THIS

DON'T DO THIS

Replace the EVAP vent solenoid with a more robust vent solenoid.

DO NOT Replace the EVAP canister or other EVAP parts.

After following the Service Manual diagnostic P0446 and determining that the EVAP canister vent valve is the cause of the SES light, replace the existing EVAP canister vent solenoid and bracket. This new vent solenoid has an enhanced filtering capability and a filter element that can be easily removed and cleaned. To ensure correct installation, follow the procedure below.

<LI type=1>Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. <LI type=1>Remove the bolt retaining the vent valve bracket. <LI type=1>Disconnect the electrical connector. <LI type=1>Disconnect the canister vent valve hose. <LI type=1>Install the new vent valve bracket, P/N 15105605, to the vehicle with the retaining bolt. Tighten
Tighten the bracket mounting bolt to 12 N·m (106 lb in).

<LI type=1>Install the new vent valve, P/N 10382105, to the bracket. <LI type=1>Reinstall the electrical connector. <LI type=1>Reinstall the canister vent valve hose. <LI type=1>Lower the vehicle.
Clear the DTC.

Parts Information

Part Number

Description

Qty

15105605

Bracket, EVAP Emission Canister Purge

1

10382105

Valve, EVAP Emission Canister Control

1

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

J6441

Valve, Evaporative Emission Canister Vent Solenoid and Bracket - Replace

Use Published Labor Operation Time

THIS WILL HELP WITH YOUR CODE ISSUE. GOOD LUCK

dichdoc · July 10, 2007

Did that repair almost six months ago with little success. Don't know if I would need to clean the thing daily to keep it open or what but I had moved on to service bullitin number one dash 2 : Take roll of black electrical tape from tool box. Cut one piece approximately .75 inches long. Move steering wheel to full down position. Apply said electrical tape to instrument cluster as to cover check engine light. Throw roll of electrical tape vigorously across room so as to avoid crying in front of wife.LOL The evap system wouldn't cause a rich condition to burn up the cat would it? I'm "hoping" the cat gave out do to the same "road" that clogs the evap valve. TB

dichdoc · July 10, 2007

Picked the Yukon up from muffler shop and he traced the sound to the Oxygen sensors (little caps rattle). Replaced both sensors and rattle is gone! I asked him about the epoxy thing and he said he hadn't had good luck with it and advised I should change them out. I let him do it for $35 in labor I wasn't about to slide under there on a creeper and mess with them. TB

Indy · July 10, 2007

I like your electrical tape idea. My light has been on for the same code for about 3 years. I check the codes once in a while to see if anything more important has come up.