P0499 - Where's the EVAP solenoid?

[Brake_L8]

Got a CEL and discovered it's for P0499, the EVAP solenoid.

I can't seem to find a definitive answer as to where the part is located on the Tahoe/Suburban/Yukon. Seems like it can be in a few different places on the pickups.

I ordered the new part ($20 from Amazon, thank you Prime shipping) but am hoping it's located somewhere easy to access.

 

[ccapehartusarmyINF.(ret)]

theres a vent valve solenoid wich is located above the rear diff
there is a purge valve solenoid wich is on top of the intake manifold
ones a tall cylindrical shaped thing

the vent valve solenoid depending on how old yer vehicle is maybe fatter cylindrical shaped
or square rectangular shaped


this one is the purge valve solenoid

the one on the left is the newer vent valve solenoid the one right is the older one

i replaced the whole evap system on my 02 tahoe and i didnt even have the one on the right i already had the newer one on the left

 

[ccapehartusarmyINF.(ret)]

and the big plastic box next to the gas tank is the charcoal canister these should always lbe the last thing you replace they are good for the life of the vehicle unless theyve bee contaminated with fuel and ive yet to see one that has been
evap system failure doesnt cause any driveability issues doesnt affect mileage or performance it is purely an emissions system wich is an annoyance all it does is puts fuel vapor back into the intake rather then to the outside open air dont sweat it
it will not cause you to fail emissions simply disconnect your battery before your emissions to clear the code go take yer emissions test and you will pass ive done it myself

 

[Brake_L8]

Based on the part number that everyone bought when getting the code, I'm replacing the "vent valve solenoid" and elected to get another of the "old style" on the right here:

So it sounds like that's above the rear diff. I'll take a look but should be easy to replace. Thanks!

 

[ccapehartusarmyINF.(ret)]

it is be careful disconnecting the hoses they have to be disconnected a certain way or plastic coupler at the end justs breaks

 

[Brake_L8]

Cool. And seems if I do break one, I can use some 5/8 tubing and hose clamps to replace the old hose(s).

 

[Brake_L8]

Managed to replace this and not break that plastic hose and clamp setup. Great success!

The CEL comes back on after two ignition cycles though. Sounds like the other Evap solenoid (near the throttle body underhood) can also throw the same code? I figure I ought to replace that one as well...

 

[SLCHOE]

and the big plastic box next to the gas tank is the charcoal canister these should always lbe the last thing you replace they are good for the life of the vehicle unless theyve bee contaminated with fuel and ive yet to see one that has been
evap system failure doesnt cause any driveability issues doesnt affect mileage or performance it is purely an emissions system wich is an annoyance all it does is puts fuel vapor back into the intake rather then to the outside open air dont sweat it
it will not cause you to fail emissions simply disconnect your battery before your emissions to clear the code go take yer emissions test and you will pass ive done it myself

I've seen fuel fouled canisters as well as others filled with dirt/sand (on Fords that see lots of dirt road usage). EVAP failures CAN cause drivability issues and if left unchecked. A stuck open purge valve is essentially a vacuum leak and would cause high fuel trims and if left unchecked long enough could cause catalytic converter damage.

Managed to replace this and not break that plastic hose and clamp setup. Great success!

The CEL comes back on after two ignition cycles though. Sounds like the other Evap solenoid (near the throttle body underhood) can also throw the same code? I figure I ought to replace that one as well...

No it's definitely a vent solenoid circuit issue. Take a good look at the wiring right as it goes into the back of the connector for the vent solenoid. Sometimes the wire breaks inside of the insulation. You can tell it's broken inside by the way it will bend very easily at a certain area (because you are basically just bending plastic).

If you cant tell, unplug the connector and check for 13-14 volts to the vent solenoid on the Orange wire with the engine running. If ok, shut off the engine and check the White wire, from the evaporative vent solenoid to pin 45 of the green PCM connector for near 0 Ohms using a multimeter.

If you don't have a multimeter you can also backprobe the connector into the white wire and supply a ground and it should click provided you have 12-14 volts on the orange wire (connector plugged in) with the engine running. It may be hard to hear the "click" of the solenoid depending on your exhaust so you may need to touch the solenoid and feel for the click instead.

 

[ccapehartusarmyINF.(ret)]

tje

Managed to replace this and not break that plastic hose and clamp setup. Great success!

The CEL comes back on after two ignition cycles though. Sounds like the other Evap solenoid (near the throttle body underhood) can also throw the same code? I figure I ought to replace that one as well...

the purge valve solenoid would throw a p0449 code usually

 

[ccapehartusarmyINF.(ret)]

I've seen fuel fouled canisters as well as others filled with dirt/sand (on Fords that see lots of dirt road usage). EVAP failures CAN cause drivability issues and if left unchecked. A stuck open purge valve is essentially a vacuum leak and would cause high fuel trims and if left unchecked long enough could cause catalytic converter damage.

i wasnt saying it doesnt happen ive just rarely seen it happen

also if you fix or replace something in the evap system dont expect the check engine light to go out right away the pcm wont test the evap system untill the drive cycle is complete

To perform an OBDII Driving cycle do the following:

1. Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
2. Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
3. Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
4. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
5. Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
6. Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
7. Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.