I'm getting codes 0491 & 0492 which are right and left bank secondary
air system failures.

Once the engine is warm, if i clear the code. They don't come back.
If it is really cold, I get the code shortly after starting, but again
if I clear it, it won;t come back.

Without Audi specific test equipment, what can I do to trouble shoot?

Fuse is good, vacuum lines all look good.

The other components are the blower, ECM, Solinoid, combi-valves. I
get both the righ and left banks so I believe it to be a fault in a
part of the system that will throw both faults. Don;t think it could
be a simultaneous right and left combi-valve failure.

No other codes. 2001 A8L, 4.2L AUX Engine.

Any thoughts?

 

If the Secondary Air Pumps are low then I would guess water or ice in the
system stopping air flow possibly due to other issues.

"JimA8L2001" <jim.rodgers@comcast.net> wrote in message
news:dc6e8c71-6188-41d6-9c41-b5b2f7851853@60g2000hsy.googlegroups.com...
> I'm getting codes 0491 & 0492 which are right and left bank secondary
> air system failures.
>
> Once the engine is warm, if i clear the code. They don't come back.
> If it is really cold, I get the code shortly after starting, but again
> if I clear it, it won;t come back.
>
> Without Audi specific test equipment, what can I do to trouble shoot?
>
> Fuse is good, vacuum lines all look good.
>
> The other components are the blower, ECM, Solinoid, combi-valves. I
> get both the righ and left banks so I believe it to be a fault in a
> part of the system that will throw both faults. Don;t think it could
> be a simultaneous right and left combi-valve failure.
>
> No other codes. 2001 A8L, 4.2L AUX Engine.
>
> Any thoughts?

 

On Mar 11, 8:05 am, "dave AKA vwdoc1" <vwdoc1nos...@pleasehotmail.com>
wrote:
> If the Secondary Air Pumps are low then I would guess water or ice in the
> system stopping air flow possibly due to other issues.
>
> "JimA8L2001" <jim.rodg...@comcast.net> wrote in message
>
> news:dc6e8c71-6188-41d6-9c41-b5b2f7851853@60g2000hsy.googlegroups.com...
>
>
>
> > I'm getting codes 0491 & 0492 which are right and left bank secondary
> > air system failures.
>
> > Once the engine is warm, if i clear the code. They don't come back.
> > If it is really cold, I get the code shortly after starting, but again
> > if I clear it, it won;t come back.
>
> > Without Audi specific test equipment, what can I do to trouble shoot?
>
> > Fuse is good, vacuum lines all look good.
>
> > The other components are the blower, ECM, Solinoid, combi-valves. I
> > get both the righ and left banks so I believe it to be a fault in a
> > part of the system that will throw both faults. Don;t think it could
> > be a simultaneous right and left combi-valve failure.
>
> > No other codes. 2001 A8L, 4.2L AUX Engine.
>
> > Any thoughts?- Hide quoted text -
>
> - Show quoted text -

Had the same problem on my 2000 A6 2.7T. In my case it was the sucker
valve (vacuum booster valve). This caused condensation to build up in
the PCV and secondary air system which froze when it got cold. The
valve I spkoe of is only on the 2.7 and 2.8 engines (I believe) but
you probably have the same condition. I went through 2 secondary air
pumps too.

 

There is a recall on failures with this system on some of the 2.8 years
and possible others. Even if you year is not covered it still should be
covered because it is a component of the pollution control system. My
son had his repaired a year ago at the dealer at no cost. It was an A4
'98.5 2.8. (replaced with an '06 A4 2.0TQ6M)

Jims Audi wrote:
> On Mar 11, 8:05 am, "dave AKA vwdoc1" <vwdoc1nos...@pleasehotmail.com>
> wrote:
>
>> If the Secondary Air Pumps are low then I would guess water or ice in the
>> system stopping air flow possibly due to other issues.
>>
>> "JimA8L2001" <jim.rodg...@comcast.net> wrote in message
>>
>> news:dc6e8c71-6188-41d6-9c41-b5b2f7851853@60g2000hsy.googlegroups.com...
>>
>>
>>
>>
>>> I'm getting codes 0491 & 0492 which are right and left bank secondary
>>> air system failures.
>>>
>>> Once the engine is warm, if i clear the code. They don't come back.
>>> If it is really cold, I get the code shortly after starting, but again
>>> if I clear it, it won;t come back.
>>>
>>> Without Audi specific test equipment, what can I do to trouble shoot?
>>>
>>> Fuse is good, vacuum lines all look good.
>>>
>>> The other components are the blower, ECM, Solinoid, combi-valves. I
>>> get both the righ and left banks so I believe it to be a fault in a
>>> part of the system that will throw both faults. Don;t think it could
>>> be a simultaneous right and left combi-valve failure.
>>>
>>> No other codes. 2001 A8L, 4.2L AUX Engine.
>>>
>>> Any thoughts?- Hide quoted text -
>>>
>> - Show quoted text -
>>
>
> Had the same problem on my 2000 A6 2.7T. In my case it was the sucker
> valve (vacuum booster valve). This caused condensation to build up in
> the PCV and secondary air system which froze when it got cold. The
> valve I spkoe of is only on the 2.7 and 2.8 engines (I believe) but
> you probably have the same condition. I went through 2 secondary air
> pumps too.
>