Hello,
P0491 is a Secondary Air System fault Bank 1.
Bank 1 refers to
the passenger side off the engine. The combination valve for secondary
air injection did not preform as it should & set a fault. The valve
is located under the plastic engine cover at the rear of the right
cylinder head.
There is a plastic tube
from the air pump to the valve that breaks, the valve sometimes fails,
there is a vacuum hose that opens the valve that also sometimes fails
& rarely the Air Injection
Vacuum Control Solenoid Valve fails. The plastic tube
unpluged/cracked or failed valve are the 2 most common failures.
If it's a vac leak it's in the small
hose from the solenoid valve
to the combination valve. The super charger may affect the vacuum, but I
would expect to see more codes if it was really messing with things.
The air injection system only runs for about 1.5 minutes on cold starts.
If the plastic tube is broken you will hear what sound like a small
exhaust leak.
P0410
What does that mean?
The P0410 code refers to the emissions system. The AIR pump puts air to the exhaust to lower emissions. It takes in outside air and pumps it through two one-way check valves into each bank of the exhaust.
About 90% of the time that this code is set, the one-way check valves have worn out or failed and allow water (which occurs naturally in the exhaust) back into the pump. In any cold climate, especially in climates with higher humidity, this water may be more excessive. The water partially fills the AIR pump, it can then freeze. When the PCM commands the pump on, if the pump is frozen it cannot turn, thus overloading the circuit and "popping" the fuse.
Symptoms
Possibly symptoms include:
* MIL illumination obviously
* Hesitation on acceleration
* Noise from a bad/stuck AIR pump
Causes
A code P0410 may mean that one or more of the following has happened:
* Water may have collected in the AIR pump or the vent solenoid and frozen or corroded the pump
* Blown AIR pump fuse due to freezing up
Possible Solutions
Note: There is a technical service bulletin (TSB) regarding this code for a number of GM models. The TSB calls for the replacement of the AIR pump and the installation of a new secondary injection hose.
Additionally, if you simply replace the AIR pump the problem may return again (and again). If you replace the pump, also clean out the hoses and replace the one-way check valve. In a few cases, people have put a small hole in the rubber cover on the pump which allows any water to drain out.
Also, please note that this may be covered under the emissions warranty on the vehicle. If your vehicle is out of bumper-to-bumper warranty, check if the emissions warranty is still valid!
* Replace the AIR pump AND one-way check valve
* Test and clean the AIR pump AND test and replace the one-way air check valve
* Replace the AIR pump inlet hose
* Replace the AIR pump fuse (found under the hood)
The above are the interpretation of the codes.
Let me know if you need further assistance.
Regards.
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