P0440 And Evap Vent Valve

schnid21 · March 22, 2009

Hoping someone can help me troubleshoot this problem.

I have been getting this code (P0440) off and on for the last month and my truck is coming due for an emission test so I need to get it fixed.

I have done quite a few searches on here and just wanted to make sure of a couple things before I start replacing parts.

My first step was to replace the fuel cap (previous owner put a lockable cap on.) I purchased a new cap from GM and this did not correct the issue.

Second step was to check the solenoid on the engine. I removed the solenoid. Looks clean and doesn't look like it has any problems. I took a 12V battery and checked to make sure the solenoid works. With 0volts I was not able to blow through the solenoid. Apply 12V, I heard a click and the valve opened (air went through). Based on this I assume the solendoid is okay. Next step was I looked at all of the hoses/tubing for signs of wear and cracks. I can't find anything but that does not mean there isn't any.

My next plan was to test the EVAP Vent Solenoid by the gas tank. I found the solenoid and started trying to remove it. Unfortunately its pretty cold here and after about an hour of trying to remove the hose from it, I gave in and decided to try another day. While working on this solenoid I removed the large hose from the charcoal canister and decided to blow into it. The air went straight through, no restriction. So my question here is how is the Solenoid mounted by the fuel tank supposed to work? Should it be closed with 0V (key off) or open with 0 Volts?

Any help with this would be appreciated.

Thanks

Jason

TexasAl · March 22, 2009

Jason,

Have you reset the trouble code after you replaced the gas cap? If not, you should reset it, and then see if it comes back.

schnid21 · March 23, 2009

Yeah, I have reset it a few times now and it keeps coming back.

schnid21 · March 24, 2009

Okay, so here is where I sit. Quite a few ppl on different forums have told me to replace the Vent solenoid close to the fuel tank because these have a pretty high chance of failing.

So I called up my dealer and the price they came back to me with was 342.00 for solenoid which is quite a bit of money to just go throwing at a part that COULD be broken.

After looking around on here I found a bunch of ppl have bought solenoids off of GM Parts Direct for $74.00 but apparently these are only good for 03 and up machines. I was wondering if anyone knows why the 02 would be so different? I have thought about buying the part of GM Part Direct and fabricating my own mounting bracket, harnesses, and hosing in order to retrofit it onto my truck. Does anyone see any reason why I couldn't or shouldn't do this?

Thanks

Jason

Norseman · March 24, 2009

Okay, so here is where I sit. Quite a few ppl on different forums have told me to replace the Vent solenoid close to the fuel tank because these have a pretty high chance of failing.

So I called up my dealer and the price they came back to me with was 342.00 for solenoid which is quite a bit of money to just go throwing at a part that COULD be broken.

After looking around on here I found a bunch of ppl have bought solenoids off of GM Parts Direct for $74.00 but apparently these are only good for 03 and up machines. I was wondering if anyone knows why the 02 would be so different? I have thought about buying the part of GM Part Direct and fabricating my own mounting bracket, harnesses, and hosing in order to retrofit it onto my truck. Does anyone see any reason why I couldn't or shouldn't do this?

Thanks

Jason

Give me a little bit and I'll check the Bulletins on this for your model truck.

schnid21 · March 24, 2009

Thanks

I really appreciate it.

Jason

chevy4life16 · October 13, 2010

i have an 02 chevy silverado z71 with 105,000 miles and i keep getting code p0440. before this i got code po446 and that is the tank vent sensor, so i cleaned it out and put it back in and the code went away for a month. then i get this p0440 code. i changed the gas cap and it still comes on, it seems like it comes on right when my truck gets around 1/2 of a tank. when i fill it up and reset the code it goes away until it hits 1/2 of a tank. can anyone help me?

txab · October 13, 2010

i have an 02 chevy silverado z71 with 105,000 miles and i keep getting code p0440. before this i got code po446 and that is the tank vent sensor, so i cleaned it out and put it back in and the code went away for a month. then i get this p0440 code. i changed the gas cap and it still comes on, it seems like it comes on right when my truck gets around 1/2 of a tank. when i fill it up and reset the code it goes away until it hits 1/2 of a tank. can anyone help me?

Might want to look over this thread

http://www.gm-trucks.com/forums/index.php?showtopic=75210

Paul P · February 16, 2011

I am in the same boat as you cold and same issue. I have eliminated the vent valve and purge valve in the system. They both function normally. I do have some tests to do that I received from a tech I know.

This is the post that I will investigate nexCustomer Concern: Trouble codes P0440 and P0449. Checked all components for connections and proper installation (gas cap), cleared codes. After two cycles code P0449 returned. Tested the evaporative vent solenoid according to a confirmed fix on the web site. the Pink wire has battery voltage. The solenoid will not click when operated by the scan tool. (Solenoid will click when ground is applied using a power probe at the White wire at the solenoid connector.) Back probed the White wire at pin 45 at the Powertrain Control Module (PCM). The voltage is 0.015 volts on or off. Ohms to ground (at alternator) 34 ohms at off and 12 Kilo ohms at on.

Tests/Procedures: 1. Test voltage at the C152 terminal F White wire.

2. Repair/replace the failed wire from the vent solenoid to the PCM.

Potential Causes: Terminal Contact

Wire

Tech Tips: C152 is a 12 cavity Blue connector locate near the Under Hood Junction Block (UHJB).

Paul P · February 16, 2011

I am trying the same things with a neighbors 2002 suburban. I have eliminated the vent and purge valves they function normally with power applied directly to them. Without a scan tool the next thing I want to try is the following.

Customer Concern: Trouble codes P0440 and P0449. Checked all components for connections and proper installation (gas cap), cleared codes. After two cycles code P0449 returned. Tested the evaporative vent solenoid according to a confirmed fix on the web site. the Pink wire has battery voltage. The solenoid will not click when operated by the scan tool. (Solenoid will click when ground is applied using a power probe at the White wire at the solenoid connector.) Back probed the White wire at pin 45 at the Powertrain Control Module (PCM). The voltage is 0.015 volts on or off. Ohms to ground (at alternator) 34 ohms at off and 12 Kilo ohms at on.

Tests/Procedures: 1. Test voltage at the C152 terminal F White wire.

2. Repair/replace the failed wire from the vent solenoid to the PCM.

Potential Causes: Terminal Contact

Wire

Tech Tips: C152 is a 12 cavity Blue connector locate near the Under Hood Junction Block (UHJB).

Sorry for the double post.