You aren't looking for a leak. You are looking primarily for a blocked vent path or inoperative vent valve or bad pressure sensor. If you will read and understand the P0446 diagnostic attachment back in post #33....... Your purge valve has built up vacuum in your fuel tank (as it should) but the P0446 says that this vacuum is trapped and doesn't vent when it is supposed to. I don't understand what a smoke machine is going to do for you? It is used to test for leaks.

You do realize that the vent valve is not the purge valve?

FROM THE P0446 DIAGNOSTIC INFO:
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.

 

Hi Les. I read your message #33. I thought that line 3 when referring to a evaporative emmisions systems tester..meant smoke machine. From what your most recent suggestion for my course of action is that isn't where or how I need to be testing. So plz just tell me at what and where I need to look, test for a way to clear this code and how to do it step by step plz. Thank you again for your time and patience and guidance. Hv a gr8 day.

 

Unless you have the equipment to do the diagnosis per the diagnostic charts (and you don't), I believe the strategy I outlined in post 34 and 38 is your best bet.

 

Fair enough, the step 4 in the chart has you pressurize the system with nitrogen using the GM supplied smoke machine. You're not using smoke but you are using the GM smoke machine. If you have the GM machine to use, that is the purge valve in your photo. I still think you will find the problem is at the vent valve or canister.

 

Man, I'm really ****ing it up. Post 34 I meant to say Evap Vent Valve NOT Evap Purge Valve. Sorry for confusion. Looks like I should stop before I get you completely confused.

 

Plz don't stop. I need all of the help I can get and I appreciate all of your help and guidance. I just need to know where and how to start identifying why my vehicle has the P0446 code come on when the evap monitor completes its cycle therefore triggering the check engine light.

 

OK i'll dig out my obd2 devices and see if I can can monitor tank pressure/vacuum and if I can control purge and vent valves on my Blazer to do an alternate diagnosis. Give me a couple of days. Car Diagnostic Pro may do what I need. Its cheap.

 

I was able to confirm that (on my 2001 Blazer) Car Diagnostic Pro will read the Fuel Tank Pressure Sensor PID, will read the Purge Valve % Operation PID, and will toggle the EVAP vent valve on/off. 2003 should be the same.

As it will require some experimentation and significant effort on my part to develop alternate diagnostic procedures, I want to ensure that you will be working with the same OBD2 software.

So get Car Diagnostic Pro from Google Play on your Android phone or tablet, and buy a Veepeak Bluetooth OBD2 device from Amazon. Enable the extended GM PIDs in the App and get it working. Then let me know and I will continue.

If you have any questions about Car Diagnostic Pro once you have the app, then post them here.

 

I have a coolant leak problem. I I can see where the coolant is leaking but I cannot tell where the leak is. I am sending a pic showing the leak that I'm describing. The leak is coming from above the pipe that it drips on to. I can not see where the leak is originating. I hope that someone has had this problem and can tell me how to fix it. I appreciate any and all help. Thank you.

 

That is most likely the radiator since it appears to be on the midline of the vehicle right above the remote oil filter bracket and not at the sides. But the leak could be anywhere on the radiator.

Radiator replacement is not hard but sure is messy.

Now would be a good opportunity to do a thorough flush of the cooling system. The ideal way requires removing a block drain plugs, one on each side, to get as much coolant out as possible. I could only get to the one on the driver's side.

You might also remove the overflow tank for a good cleaning.