Bypass solenoid valve
 

Hi,

I just was told that my bypass solenoid valve was bad and needed to be
replaced. First of all, what is it and what does it do? The
mechanic's accent was so thick that I could barely understand what he
was saying. I know it is part of the EVAP but I am not sure of its
function.

Please help!

j.

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:

> Hi,
>
> I just was told that my bypass solenoid valve was bad and needed to be
> replaced. First of all, what is it and what does it do? The
> mechanic's accent was so thick that I could barely understand what he
> was saying. I know it is part of the EVAP but I am not sure of its
> function.
>


Year? Make? Model?

Is this a Honda?

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:

> Hi,
>
> I just was told that my bypass solenoid valve was bad and needed to be
> replaced. First of all, what is it and what does it do? The
> mechanic's accent was so thick that I could barely understand what he
> was saying. I know it is part of the EVAP but I am not sure of its
> function.
>


Year? Make? Model?

Is this a Honda?

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:

> Hi,
>
> I just was told that my bypass solenoid valve was bad and needed to be
> replaced. First of all, what is it and what does it do? The
> mechanic's accent was so thick that I could barely understand what he
> was saying. I know it is part of the EVAP but I am not sure of its
> function.
>


Year? Make? Model?

Is this a Honda?

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:

> Hi,
>
> I just was told that my bypass solenoid valve was bad and needed to be
> replaced. First of all, what is it and what does it do? The
> mechanic's accent was so thick that I could barely understand what he
> was saying. I know it is part of the EVAP but I am not sure of its
> function.
>



Don't wanna tell me what year and model? Oh well.

The EVAP system regularly applies vacuum to the vapor purge tank to clean
it out. This vacuum must not be allowed to pull new vapors from the gas
tank during this operation, so there is a "vacuum cut solenoid valve" to
block vacuum from reaching the gas tank.
When the EVAP system does its "self test", it needs to be able to apply
vacuum to the tank to check for leaks, so it has to override the "vacuum
cut solenoid valve". The bypassing is done by the "bypass solenoid valve".

If the bypass was bad, the ECM probably saw the wrong voltage values from
other sensors in the system, and it then knew to turn on your Check Engine
light with an error code.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:

> Hi,
>
> I just was told that my bypass solenoid valve was bad and needed to be
> replaced. First of all, what is it and what does it do? The
> mechanic's accent was so thick that I could barely understand what he
> was saying. I know it is part of the EVAP but I am not sure of its
> function.
>



Don't wanna tell me what year and model? Oh well.

The EVAP system regularly applies vacuum to the vapor purge tank to clean
it out. This vacuum must not be allowed to pull new vapors from the gas
tank during this operation, so there is a "vacuum cut solenoid valve" to
block vacuum from reaching the gas tank.
When the EVAP system does its "self test", it needs to be able to apply
vacuum to the tank to check for leaks, so it has to override the "vacuum
cut solenoid valve". The bypassing is done by the "bypass solenoid valve".

If the bypass was bad, the ECM probably saw the wrong voltage values from
other sensors in the system, and it then knew to turn on your Check Engine
light with an error code.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:

> Hi,
>
> I just was told that my bypass solenoid valve was bad and needed to be
> replaced. First of all, what is it and what does it do? The
> mechanic's accent was so thick that I could barely understand what he
> was saying. I know it is part of the EVAP but I am not sure of its
> function.
>



Don't wanna tell me what year and model? Oh well.

The EVAP system regularly applies vacuum to the vapor purge tank to clean
it out. This vacuum must not be allowed to pull new vapors from the gas
tank during this operation, so there is a "vacuum cut solenoid valve" to
block vacuum from reaching the gas tank.
When the EVAP system does its "self test", it needs to be able to apply
vacuum to the tank to check for leaks, so it has to override the "vacuum
cut solenoid valve". The bypassing is done by the "bypass solenoid valve".

If the bypass was bad, the ECM probably saw the wrong voltage values from
other sensors in the system, and it then knew to turn on your Check Engine
light with an error code.

--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

Greetings,

Thank you for the thorough response. By the way, It's a '99 Accord
Coupe, 4cyl. I didn't realize that this part would perform different
functions in different cars, which is why I neglected to provide the
model and year.

How often does the EVAP system do a self test?

When you say, "it needs to be able to apply vacuum to the tank..." Are
you talking about the vapor purge tank or gas tank? I would assume the
gas tank since it overrides the vacuum valve, which prevents access to
it.

Also...the vapor purge tank. How are there "extra" vapors where they
need their own tank?

Thanks again!

Jessica

TeGGeR® wrote:
> "Jess" <jlhick20@yahoo.com> wrote in
> news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:
>
> > Hi,
> >
> > I just was told that my bypass solenoid valve was bad and needed to be
> > replaced. First of all, what is it and what does it do? The
> > mechanic's accent was so thick that I could barely understand what he
> > was saying. I know it is part of the EVAP but I am not sure of its
> > function.
> >
>
>
>
> Don't wanna tell me what year and model? Oh well.
>
> The EVAP system regularly applies vacuum to the vapor purge tank to clean
> it out. This vacuum must not be allowed to pull new vapors from the gas
> tank during this operation, so there is a "vacuum cut solenoid valve" to
> block vacuum from reaching the gas tank.
> When the EVAP system does its "self test", it needs to be able to apply
> vacuum to the tank to check for leaks, so it has to override the "vacuum
> cut solenoid valve". The bypassing is done by the "bypass solenoid valve".
>
> If the bypass was bad, the ECM probably saw the wrong voltage values from
> other sensors in the system, and it then knew to turn on your Check Engine
> light with an error code.
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

Greetings,

Thank you for the thorough response. By the way, It's a '99 Accord
Coupe, 4cyl. I didn't realize that this part would perform different
functions in different cars, which is why I neglected to provide the
model and year.

How often does the EVAP system do a self test?

When you say, "it needs to be able to apply vacuum to the tank..." Are
you talking about the vapor purge tank or gas tank? I would assume the
gas tank since it overrides the vacuum valve, which prevents access to
it.

Also...the vapor purge tank. How are there "extra" vapors where they
need their own tank?

Thanks again!

Jessica

TeGGeR® wrote:
> "Jess" <jlhick20@yahoo.com> wrote in
> news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:
>
> > Hi,
> >
> > I just was told that my bypass solenoid valve was bad and needed to be
> > replaced. First of all, what is it and what does it do? The
> > mechanic's accent was so thick that I could barely understand what he
> > was saying. I know it is part of the EVAP but I am not sure of its
> > function.
> >
>
>
>
> Don't wanna tell me what year and model? Oh well.
>
> The EVAP system regularly applies vacuum to the vapor purge tank to clean
> it out. This vacuum must not be allowed to pull new vapors from the gas
> tank during this operation, so there is a "vacuum cut solenoid valve" to
> block vacuum from reaching the gas tank.
> When the EVAP system does its "self test", it needs to be able to apply
> vacuum to the tank to check for leaks, so it has to override the "vacuum
> cut solenoid valve". The bypassing is done by the "bypass solenoid valve".
>
> If the bypass was bad, the ECM probably saw the wrong voltage values from
> other sensors in the system, and it then knew to turn on your Check Engine
> light with an error code.
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

Greetings,

Thank you for the thorough response. By the way, It's a '99 Accord
Coupe, 4cyl. I didn't realize that this part would perform different
functions in different cars, which is why I neglected to provide the
model and year.

How often does the EVAP system do a self test?

When you say, "it needs to be able to apply vacuum to the tank..." Are
you talking about the vapor purge tank or gas tank? I would assume the
gas tank since it overrides the vacuum valve, which prevents access to
it.

Also...the vapor purge tank. How are there "extra" vapors where they
need their own tank?

Thanks again!

Jessica

TeGGeR® wrote:
> "Jess" <jlhick20@yahoo.com> wrote in
> news:1155046318.744392.31650@p79g2000cwp.googlegro ups.com:
>
> > Hi,
> >
> > I just was told that my bypass solenoid valve was bad and needed to be
> > replaced. First of all, what is it and what does it do? The
> > mechanic's accent was so thick that I could barely understand what he
> > was saying. I know it is part of the EVAP but I am not sure of its
> > function.
> >
>
>
>
> Don't wanna tell me what year and model? Oh well.
>
> The EVAP system regularly applies vacuum to the vapor purge tank to clean
> it out. This vacuum must not be allowed to pull new vapors from the gas
> tank during this operation, so there is a "vacuum cut solenoid valve" to
> block vacuum from reaching the gas tank.
> When the EVAP system does its "self test", it needs to be able to apply
> vacuum to the tank to check for leaks, so it has to override the "vacuum
> cut solenoid valve". The bypassing is done by the "bypass solenoid valve".
>
> If the bypass was bad, the ECM probably saw the wrong voltage values from
> other sensors in the system, and it then knew to turn on your Check Engine
> light with an error code.
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155127138.568581.274550@b28g2000cwb.googlegr oups.com:

> Greetings,
>
> Thank you for the thorough response. By the way, It's a '99 Accord
> Coupe, 4cyl. I didn't realize that this part would perform different
> functions in different cars, which is why I neglected to provide the
> model and year.


Performs the same function in all vehicles with that type of EVAP. But...

It's *always* a good idea when posting questions to state year, model, trim
level, transmission and presence or absence of A/C. Engine controls differ
given the above. This way some of us can look to see if there are known
problems, gotchas, or TSBs involving your ride.


>
> How often does the EVAP system do a self test?



Don't know for sure, but I think it's at least once per trip.



>
> When you say, "it needs to be able to apply vacuum to the tank..." Are
> you talking about the vapor purge tank or gas tank? I would assume
> the gas tank since it overrides the vacuum valve, which prevents
> access to it.


Correct.


>
> Also...the vapor purge tank. How are there "extra" vapors where they
> need their own tank?


There aren't any "extra" vapors. All fuel tank vapors end up in the
charcoal canister that is called the "purge tank". This is the entire
purpose of the EVAP system.

It's just that when the EVAP system attempts to drain the purge tank of its
existing vapors, it makes no sense to allow new vapors into the purge tank
at the same time. That would be a bit like pulling the plug on your
bathroom sink while turning the tap on at the same time.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155127138.568581.274550@b28g2000cwb.googlegr oups.com:

> Greetings,
>
> Thank you for the thorough response. By the way, It's a '99 Accord
> Coupe, 4cyl. I didn't realize that this part would perform different
> functions in different cars, which is why I neglected to provide the
> model and year.


Performs the same function in all vehicles with that type of EVAP. But...

It's *always* a good idea when posting questions to state year, model, trim
level, transmission and presence or absence of A/C. Engine controls differ
given the above. This way some of us can look to see if there are known
problems, gotchas, or TSBs involving your ride.


>
> How often does the EVAP system do a self test?



Don't know for sure, but I think it's at least once per trip.



>
> When you say, "it needs to be able to apply vacuum to the tank..." Are
> you talking about the vapor purge tank or gas tank? I would assume
> the gas tank since it overrides the vacuum valve, which prevents
> access to it.


Correct.


>
> Also...the vapor purge tank. How are there "extra" vapors where they
> need their own tank?


There aren't any "extra" vapors. All fuel tank vapors end up in the
charcoal canister that is called the "purge tank". This is the entire
purpose of the EVAP system.

It's just that when the EVAP system attempts to drain the purge tank of its
existing vapors, it makes no sense to allow new vapors into the purge tank
at the same time. That would be a bit like pulling the plug on your
bathroom sink while turning the tap on at the same time.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

"Jess" <jlhick20@yahoo.com> wrote in
news:1155127138.568581.274550@b28g2000cwb.googlegr oups.com:

> Greetings,
>
> Thank you for the thorough response. By the way, It's a '99 Accord
> Coupe, 4cyl. I didn't realize that this part would perform different
> functions in different cars, which is why I neglected to provide the
> model and year.


Performs the same function in all vehicles with that type of EVAP. But...

It's *always* a good idea when posting questions to state year, model, trim
level, transmission and presence or absence of A/C. Engine controls differ
given the above. This way some of us can look to see if there are known
problems, gotchas, or TSBs involving your ride.


>
> How often does the EVAP system do a self test?



Don't know for sure, but I think it's at least once per trip.



>
> When you say, "it needs to be able to apply vacuum to the tank..." Are
> you talking about the vapor purge tank or gas tank? I would assume
> the gas tank since it overrides the vacuum valve, which prevents
> access to it.


Correct.


>
> Also...the vapor purge tank. How are there "extra" vapors where they
> need their own tank?


There aren't any "extra" vapors. All fuel tank vapors end up in the
charcoal canister that is called the "purge tank". This is the entire
purpose of the EVAP system.

It's just that when the EVAP system attempts to drain the purge tank of its
existing vapors, it makes no sense to allow new vapors into the purge tank
at the same time. That would be a bit like pulling the plug on your
bathroom sink while turning the tap on at the same time.


--
TeGGeR®

The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

Thank you so much for your help! I really appreciate it.

I checked out your website and was fascinated with all the FAQs! I,
too, have a buzz at certain RPMs (typically when I'm at a low speed in
2nd or 3rd) in the rear of my car. I wonder if I have the Honda
"A-pipe" rattle?

My friend said something about Honda offering a "buzz" kit to fix the
problem but I never looked into it because it didn't seem all that
problematic.

Thanks again!

Jessica

TeGGeR® wrote:
> "Jess" <jlhick20@yahoo.com> wrote in
> news:1155127138.568581.274550@b28g2000cwb.googlegr oups.com:
>
> > Greetings,
> >
> > Thank you for the thorough response. By the way, It's a '99 Accord
> > Coupe, 4cyl. I didn't realize that this part would perform different
> > functions in different cars, which is why I neglected to provide the
> > model and year.
>
>
> Performs the same function in all vehicles with that type of EVAP. But...
>
> It's *always* a good idea when posting questions to state year, model, trim
> level, transmission and presence or absence of A/C. Engine controls differ
> given the above. This way some of us can look to see if there are known
> problems, gotchas, or TSBs involving your ride.
>
>
> >
> > How often does the EVAP system do a self test?
>
>
>
> Don't know for sure, but I think it's at least once per trip.
>
>
>
> >
> > When you say, "it needs to be able to apply vacuum to the tank..." Are
> > you talking about the vapor purge tank or gas tank? I would assume
> > the gas tank since it overrides the vacuum valve, which prevents
> > access to it.
>
>
> Correct.
>
>
> >
> > Also...the vapor purge tank. How are there "extra" vapors where they
> > need their own tank?
>
>
> There aren't any "extra" vapors. All fuel tank vapors end up in the
> charcoal canister that is called the "purge tank". This is the entire
> purpose of the EVAP system.
>
> It's just that when the EVAP system attempts to drain the purge tank of its
> existing vapors, it makes no sense to allow new vapors into the purge tank
> at the same time. That would be a bit like pulling the plug on your
> bathroom sink while turning the tap on at the same time.
>
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/

Re: Bypass solenoid valve
 

Thank you so much for your help! I really appreciate it.

I checked out your website and was fascinated with all the FAQs! I,
too, have a buzz at certain RPMs (typically when I'm at a low speed in
2nd or 3rd) in the rear of my car. I wonder if I have the Honda
"A-pipe" rattle?

My friend said something about Honda offering a "buzz" kit to fix the
problem but I never looked into it because it didn't seem all that
problematic.

Thanks again!

Jessica

TeGGeR® wrote:
> "Jess" <jlhick20@yahoo.com> wrote in
> news:1155127138.568581.274550@b28g2000cwb.googlegr oups.com:
>
> > Greetings,
> >
> > Thank you for the thorough response. By the way, It's a '99 Accord
> > Coupe, 4cyl. I didn't realize that this part would perform different
> > functions in different cars, which is why I neglected to provide the
> > model and year.
>
>
> Performs the same function in all vehicles with that type of EVAP. But...
>
> It's *always* a good idea when posting questions to state year, model, trim
> level, transmission and presence or absence of A/C. Engine controls differ
> given the above. This way some of us can look to see if there are known
> problems, gotchas, or TSBs involving your ride.
>
>
> >
> > How often does the EVAP system do a self test?
>
>
>
> Don't know for sure, but I think it's at least once per trip.
>
>
>
> >
> > When you say, "it needs to be able to apply vacuum to the tank..." Are
> > you talking about the vapor purge tank or gas tank? I would assume
> > the gas tank since it overrides the vacuum valve, which prevents
> > access to it.
>
>
> Correct.
>
>
> >
> > Also...the vapor purge tank. How are there "extra" vapors where they
> > need their own tank?
>
>
> There aren't any "extra" vapors. All fuel tank vapors end up in the
> charcoal canister that is called the "purge tank". This is the entire
> purpose of the EVAP system.
>
> It's just that when the EVAP system attempts to drain the purge tank of its
> existing vapors, it makes no sense to allow new vapors into the purge tank
> at the same time. That would be a bit like pulling the plug on your
> bathroom sink while turning the tap on at the same time.
>
>
> --
> TeGGeR®
>
> The Unofficial Honda/Acura FAQ
> www.tegger.com/hondafaq/