Engine check light with code P0440?

Tiny
RWALBROEHL
  • MEMBER
  • 2006 CHEVROLET S-10
  • 2.2L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 70,000 MILES
Check engine light. The scanner says code P0440. Don't know where its located-on the engine. Could a vacuum line to it be a problem? Any way to further troubleshoot it before buying the part?
Wednesday, November 22nd, 2023 AT 9:50 AM

9 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

I need confirmation of the model year. The S10 wasn't offered in 2006. I have a feeling you meant 1996, so that is what I went with.

If that is incorrect, let me know. If it is correct, I attached the diagnostics below specific to the code. It could be several things causing it related to the evaporative emissions system. If I had to guess, I would say either the fuel cap is leaking, the vapor canister is faulty, or the canister vent valve is stuck

Let me know and Happy Thanksgiving.

Joe

See pics below.
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Wednesday, November 22nd, 2023 AT 9:58 PM
Tiny
RWALBROEHL
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My S-10 is a 2003. Automatic 4 cylinder 2.2L. I went to AutoZone, and they said the code was PO440. Ticket came back to Replace Evaporation. Emission (EVAP) Purge Solenoid followed by Canister Purge Valve. I don't know where that is even located on the truck or how to check it before spending the money to buy it. So now I don't know which one to change first. It sounds to me that these are two different parts. Please help.
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Thursday, November 23rd, 2023 AT 6:13 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

Okay, on the 2003, the P0440 indicates a large EVAP leak. This could be either of the things you indicated above but it is more likely a broken or disconnected hose.

I attached two pics below showing the vacuum schematic for the EVAP system. These hoses run from the fuel tank to the engine compartment. The canister purge valve is mounted under the hood next to the ignition coils.

I attached the directions below for replacing it. However, here is what I recommend. First, inspect the hoses visually for damage. If nothing is found, have the EVAP system smoke tested. Basically, smoke is injected into the EVAP system at a low pressure. Wherever the leak is located, the smoke will show up.

If that doesn't prove beneficial, then the components need to be tested. As far as testing the components, it requires a bidirectional scan tool that can actuate them on request. Is that something you may have?

Let me know if this helps.

Take care,

Joe

See pics below.
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Thursday, November 23rd, 2023 AT 9:17 PM
Tiny
RWALBROEHL
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  • 44 POSTS
Still does not help. Can't find items in truck. YouTube says around ignition coil. Another video shows a unit at the gas tank area underneath. Obviously, there are two units. Canister purge valve and then a vent solenoid. Totally lost.
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Friday, November 24th, 2023 AT 8:41 AM
Tiny
RWALBROEHL
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  • 44 POSTS
Code PO440 is supposed to be a canister purge valve.
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Friday, November 24th, 2023 AT 8:43 AM
Tiny
RWALBROEHL
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  • 44 POSTS
I do not like GM products, they are much more difficult than Toyotas.
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Friday, November 24th, 2023 AT 8:44 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

You are correct. It's the canister purge valve. It should be on the right side of the engine compartment. It's mounted right next to the ignition coils.

Take a pic of the coils so I can see what you are dealing with. Maybe I'll recognize it for you.

Let me know.

Joe
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Friday, November 24th, 2023 AT 7:11 PM
Tiny
RWALBROEHL
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Okay. Then first chance I get. Recovering from kidney stone.
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Saturday, November 25th, 2023 AT 6:30 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

Kidney stone? Ugh! Extremely painful. I hope you're feeling better.

No rush. I'll be here.

Joe
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Saturday, November 25th, 2023 AT 9:01 PM

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