P0449? What's the cause/fix?

[terry_b]

So I got CEL the other morning on my way home from work, took it to AutoZone and I've got a P0449 code - Evaporative Emission Control System Vent Valve/Solenoid Circuit

Anybody know what a likely cause is? Also how severe?

I can't make it to the dealer until Friday at the earliest, but if its a simple problem, easily remedied, then I won't bother with the trip at all.

Thanks in advance!

[Nutbutt]

Sound like gas cap issue ? Have you checked the cap to make sure it's on ?
It should reset itself after awhile.

[Mr_Draco]

It's 1 of 3 things.

1) Loose gas cap
2) Evap. Emission canister. I haven't looked on the Camaro but I've had this issue on a couple other cars and was able to replace it myself.
3) Evap. Emission solenoid. This is located inside the gas tank and requires the gas tank to be removed.

The most likely cause is the 1st one, with the next likely being the 2nd one. Solenoids do go bad but it's rare.

[Iam Broke]

Evap Purge Sol is mounted on the front pass side of the LS3 as I recall from relocating it for my SC. Never heard of one in the tank but I'm old & a feeb.

[Mr_Draco]

Originally Posted by Iam Broke

Evap Purge Sol is mounted on the front pass side of the LS3 as I recall from relocating it for my SC. Never heard of one in the tank but I'm old & a feeb.

The op is asking about Evap. Emission.

Evap. Purge and Evap. Emission is two different things. This is like the op asking about the fuel filter and you coming on and giving him info on the oil filter.

[terry_b]

So I did check the gas cap before leaving for work today... light is still in. Is there a way to clear the light manually? Remove negative battery cable maybe and see if it goes away?

Is this something the powertrain warranty covers? I'm well past the bumper to bumper, but still within the powertrain coverage?

We're talking about emission stuff, so I imagine this is semi-important but not terrible if I drive the car all week correct? I have to drive to work until Thursday...

After some Google searches,the best results coming right from Camaro5 of course, this looks like a common GM problem, not necessarily warrantied. Well shoot... if it is just the canister, does anybody have any experience replacing it? From what I read canister is cheap, solenoid quite the opposite.

[etmx183]

1. The KEY word in the code is CIRCUIT the pcm is not seeing correct voltage in the circuit. so we are talking wiring, solenoid or computer.
   
   
   P0449
   
2. Ignition ON, engine OFF, command the EVAP vent solenoid valve to Not Venting and Venting with a scan tool. Listen for a click when the valve operates.
3. Verify that both the Venting and the Not Venting states are commanded with a scan tool and their parameter status should display OK or Not Run.
   • EVAP Vent Solenoid Circuit Short To Ground Test Status
   • EVAP Vent Solenoid Circuit Open Test Status
   • EVAP Vent Solenoid Circuit Short To Voltage Test Status
4. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at,
   • The Q12 evaporative emission purge solenoid valve for P0443
   • The Q13 evaporative emission vent solenoid valve for P0449
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal and ground.
   ⇒X If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the evaporative emission canister purge solenoid valve.
3. Connect a test lamp between the voltage supply circuit terminal and the control circuit terminal.
4. With a scan tool command the,
   • EVAP purge solenoid valve to 50 %
   • EVAP vent solenoid valve to Venting and Not VentingThe test lamp should respond to the command.
5. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
6. If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
7. If all circuits test normal, replace the appropriate solenoid valve.

[etmx183]

Diagnostic Fault Information


Circuit
Short to Ground
High Resistance
Open
Short to Voltage
Signal Performance
Ignition 1 Voltage – Purge Supply
P0443
P0443
P0443
—
—
Battery Positive – Vent Supply
P0449
P0449
P0449
—
—
Evaporative Emission Purge Solenoid Valve Control
P0443
P0443
P0443
—
—
Evaporative Emission Vent Solenoid Valve Control
P0449
P0449
P0449
P0449
—
Circuit/System Description

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The engine control module (ECM) grounds the evaporative emission canister purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The evaporative emission canister purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.
Battery voltage is supplied to the evaporative emission canister vent solenoid valve. The ECM grounds the evaporative emission canister vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the evaporative emission canister vent solenoid valve as ON or OFF.
Conditions for Running the DTC

• The ignition is ON.
• The system voltage is greater than 11 V.
• DTCs P0443 and P0449 run continuously when the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 5 s.
Action Taken When the DTC Sets

DTCs P0443 and P0449 are Type B DTCs.
Conditions for Clearing the MIL/DTC

DTCs P0443 and P0449 are Type B DTCs.
Reference Information

Schematic Reference

[Mr_Draco]

Originally Posted by terry_b

So I did check the gas cap before leaving for work today... light is still in. Is there a way to clear the light manually? Remove negative battery cable maybe and see if it goes away?

Is this something the powertrain warranty covers? I'm well past the bumper to bumper, but still within the powertrain coverage?

We're talking about emission stuff, so I imagine this is semi-important but not terrible if I drive the car all week correct? I have to drive to work until Thursday...

After some Google searches,the best results coming right from Camaro5 of course, this looks like a common GM problem, not necessarily warrantied. Well shoot... if it is just the canister, does anybody have any experience replacing it? From what I read canister is cheap, solenoid quite the opposite.

You can disconnect the battery for awhile and it should reset or you can go by Autozone or Advance Auto and they can reset it.

It is not related to the powertrain so most likely not.

You'll be fine driving it this way. My dad's Impala had the same issue and he drove it for months before getting it fixed. You'll have trouble getting gas when you fill up but it won't effect driving in the least.

I have not looked at the Camaro, but on other vehicles I've done it was really easy. If you have a set of ramps, you could probably do it yourself in 30 mins.

[terry_b]

Thanks, I appreciate the help! It's good to know it's not a major issue. I'll try disconnecting the battery tonight. If was just the gas cap it probably would've gone away on it's own right?

[SSMickey]

For the light to turn off on it's own, the ECU will have to run and pass the test that caused the light twice. Without a scan tool, it wil be hard to know if that has happened. Find a scan tool and reset the light or disconnect your battery. If you disconnect your battery though, you will most likely lose your radio presets and window indexing. Better to reset the light with a scan tool.

[camarosspower]

I have this same problem too. What are the chances that the gas cap went bad?

[thahemp]

Originally Posted by Mr_Draco

You can disconnect the battery for awhile and it should reset or you can go by Autozone or Advance Auto and they can reset it.

It is not related to the powertrain so most likely not.

You'll be fine driving it this way. My dad's Impala had the same issue and he drove it for months before getting it fixed. You'll have trouble getting gas when you fill up but it won't effect driving in the least.

I have not looked at the Camaro, but on other vehicles I've done it was really easy. If you have a set of ramps, you could probably do it yourself in 30 mins.

Last time I was at Autozone with a code.. the guy said they aren't supposed to clear them. I thought that was kinda lame, but I suppose from a liability standpoint it makes sense.

[camarosspower]

Does anybody know where these sensors located on the car??