04 chevy avalanche. failed inspection. OBD11

Nathan, 2 Knock's are located under intake manifold.
Check the attached links,
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How To Install Replace Engine Knock Sensor 2000 06 5 3L Silverado Sierra...

Knock sensor 5 3 4 8 6 0 replacement

05 Chevy Avalanche Knock Sensors

4 8 5 3 6 0 knock sensor replacement GM

Chevy Avalanche 2002 2006 Factory Service Workshop repair manual

for the easy solution download the pdf file

YOU REPLACED PARTS FOR NOTHING ! P0446 Chevrolet Evaporative Emission Vent System Performance Chevy Impala Check Engine Light Codes P0446 P0451 EVAP Trouble HERE WATCH A REAL TECH.

go to ask.com, or about.com, wiki.com ant type in the following info on address bar or web site: 2003 chevy avalnche 5.3 code po343 and it will give you an answer if the code has every been searched for.

P0452 evap control pressure low, P0 446 evap vent contol circuit. Becuase you have P0452 you are dealing with a eletrical issue whether you have positive tank pressure or negative pressure, The tool for this is a volt meter.452 happens when you positive pressure and the FTP reads less than 0.1 volts.You need to jump the signal and the reference and monitor the take parameter on a scan data you should read reference voltage.Now if you dont have a scan data tool. inspect the wire for any breaks or shorting 2 thing of concern broken wire to the FTP or a ECM is needed.

It is probably the evap vent valve. A new vent solenoid valve has been redesigned to correct the problem you are having. I would recommend purchasing the dealer component.
I hope this helps.

All these codes indicate that maybe you lost your reference signal from the computer. What someone will have to do is check fo voltage and grounds from the PCM on the coolant temp sensor, Both 02 sensor heater circuits, the evap purge solenoid and the gas tank pressure sensor. Its possble the computer failed or you poped a PCM fuse in the fuse box under the hood. The cover should have a legend to tell you which is which but I would pull all of them and inspect anyways.

It is for the canister vent solenoid. Gm has a service bulletin out on this. They have changed the location of the solenoid. They have a repair kit for about 100 dollars that comes with the solenoid and the lines and instructions for moving the solenoid to its new location.

what is trouble shooting code po894 for 2005 chevy avalanche

if the air filter was recently inspected or changed, look for the vacuum hose to be disconnected from the valve located on the air filter cover. another source may be the gas cap either loose or with the tether strap caught under it preventing a proper seal