Mazdax605 UltraDork
5/31/16 4:40 p.m.

Hey guys,

Had the check engine light come on in the suburban this afternoon. I pulled over and connected my Bluetooth obdII scanner to the port and started up torque pro. Came up with this code. Not sure what it means, but a web search showed evap vent solenoid control circuit condition. Not really knowing what that meant I sort of blindly just cleared the code. It didn't come back in during the rest of the trip. Any clue if this will come back? If so what should I be looking to repair?

iceracer PowerDork
5/31/16 5:40 p.m.

sounds like you may have a poor connection in the solenoid circuit.

Evap codes can be spotty. there now, not there later.

Ranger50 UltimaDork
5/31/16 6:07 p.m.

Spend the $50 and put on another.

Mazdax605 UltraDork
5/31/16 6:55 p.m.

Another what?

Doc Brown
Doc Brown Dork
5/31/16 9:54 p.m.

Try tightening the gas cap

lnlogauge Reader
5/31/16 9:59 p.m.

I didn't know Evap codes was a thing, until my 4runner decided to throw them at me. Try the gas cap first. If you have a leak, it can be a pita to find. I paid the dealer to run a smoke test. 120.00 later, a 400 piece of plastic and charcoal was replaced.

NickD Dork
6/1/16 5:21 a.m.

If it's a Vent Solenoid Circuit code, it's not going to be a gas cap, like people are saying. The ECU is detecting a circuit fault within the Vent Valve Solenoid's circuit. Most likely it is either a corroded connector at the vent valve or the vent valve itself has gotten stuck in one position (If there is no P0442 EVAP Small Leak or P0455 EVAP Large Leak, it's likely stuck closed). Vent valve solenoids are a common failure in GM trucks, we do a lot of them.

Mazdax605 UltraDork
6/1/16 5:28 a.m.

Where is that vent valve located?

NickD Dork
6/1/16 6:23 a.m.

If you have a san tool capable of commanding the vent valve, you can test it easily. Command it back and forth between on and off and it should make an audible snap as it opens and closes. If it doesn't, then hook a test light or noid light between the terminals of the connector. If the light illuminates, you need a vent valve. But the fact that you have a circuit code makes me think that it's most likely bad, barring wiring damage elsewhere.

Mazdax605 UltraDork
6/1/16 5:22 p.m.

I don't think my $20 amazon purchased obdII Bluetooth scanner is capable of commanding the valve on and off. With that being said, if it were bad, how soon after resetting the check engine light would it come back on if the valve was truly bad/malfunctioning?

The Hoff
The Hoff UltraDork
6/1/16 5:29 p.m.

P0449 EVAP Vent Solenoid Control Circuit Malfunction - Automatic Transmission Possible Causes Setting Conditions

EVAP vent control circuit is open or it has high resistance

EVAP Vent solenoid has failed

EVAP vent control circuit is shorted to voltage

EVAP vent solenoid Ignition circuit is open (check the 4WS fuse in fuse block)

PCM has failed

Engine speed over 400 rpm; system voltage from 6-18v, and the PCM detected that the Actual and Commanded state of the Vent Solenoid control circuit did not match for 5 seconds. Ignition voltage is supplied to the EVAP canister vent solenoid valve. The PCM grounds the vent solenoid valve control circuit to close the valve by means of an internal switch called a driver.

Bobzilla UltimaDork
6/1/16 5:30 p.m.

iT'S A common thing on this body style truck/burb/hoe. I had to replace ours on the 06 CC. what happens is the filter for the evap solenoid is part of the solenoid. It fills up, then gums up the sloenoid so it no longer works. Living in dusty conditions (like our gravel road) only make this happen faster. There is a 2 part replacement that requires a foot of 5/8" heater hose, a couple clamps and anbout 15 minutes of time. I got mine off Amazon for $40.

Mazdax605 UltraDork
6/5/16 11:54 a.m.

Light still hasn't come back on since I reset it. Maybe it was a fluke? Unlikely I know.


Jerry From LA
Jerry From LA Dork
6/5/16 12:16 p.m.

If you read the explanation the The Hoff published, the actual and commanded state of the VSV circuit did not match for five seconds or more. Your VSV may have hung, then righted itself.

This is a known problem on many Toyotas, although the fix isn't as cheap because the VSV is molded into the whole canister. My stepdaughter's Corolla has thrown this code. I just clear it and it doesn't come back. In the event it comes on and stays on, I'll attend to it then.

Knurled MegaDork
6/5/16 1:55 p.m.

The vent solenoid gets power all the time, the computer controls the ground side. The computer also monitors the ground side to see if there is voltage on that return wire - it knows the voltage going in and an acceptable range of resistance going through the solenoid. If it sees high or no voltage, that is a circuit fault.

Check the resistance of the solenoid, then trace along the wires going to it and look for corrosion ("green death"). Circuit codes are USUALLY damaged wiring. A blown fuse can also cause it, but that usually results in many more circuits losing power too.

Vent solenoids, especially GM truck vent solenoids, usually fail by not sealing due to debris in them. That doesn't cause a circuit code, that causes a leak. It's still possible that the internal coil is failing and has high resistance, or low resistance, or intermittently high or low resistance...

Either way, if it isn't acting up now, you won't be able to find out what it is, so I wouldn't worry about it until it comes right back again.

keethrax Dork
6/6/16 10:07 a.m.
Mazdax605 wrote: Light still hasn't come back on since I reset it. Maybe it was a fluke? Unlikely I know. Chris

Ours always seemed to get stuck once or twice when the weather had big swings and then just work again.

Mazdax605 UltraDork
1/23/17 6:26 a.m.

So on Friday or Saturday I forget which this code popped back up again. I reset it thinking well it worked back in June, maybe it will again. I came right back in on Sunday. I'm guessing I should just replace this part now. It has been unseasonably warm around these parts however, so maybe that has something to do with it. I will order the part. Any suggestions as to who to get the part from? Best to go dealer/factory, or is aftermarket okay on this part?

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