2009 ford fusion code p0491 = secondary air injection system bank one. The dealership put in a secondary air injection pump assembly and the code is still there? I saw where this code is the check v

codes p 0410, 0411, 0412 all refer to the secondary air injection system--malfunction, incorrect flow detected and circuit malfunction ===causes are --wiring--sir valve---air solenoid--ECM--air pump, air hose/s--ECM
code p 0491 refers to secondary air injection bank 1 --malfunction or insufficient flow=== causes are the same with a mechanical fault added
so to analyze -- the most common cause is air hoses, followed by valve or solenoid of the air injection system followed by ECM which be as little as a bad pin connection in the wiring

bank 1 is the side of the number 1 cylinder ---you didnt specify vehicle but this is a generic code and the following link will help you in solving your problem
P0491 Secondary Air Injection System Insufficient Flow Bank 1

P0491 - Secondary Air Injection System Insufficient Flow Bank 1
Possible causes
- Intake leak
- Damaged AIR system components
- Faulty AIR Solenoid Valve
- Faulty AIR system relay

Both of those codes refer to a problem with the secondary air system (air pump). The P0491 refers specifically to bank 1. Both codes are generic in nature and don't tell you anything specific about the problem so the whole system has to be troubleshooted. Look for damaged hoses or vacuum lines off for starters.

P0491 Secondary Air Injection System (Bank 1)
P0492 Secondary Air Injection System (Bank 2)
Good luck for you!
OBD2 code reader

Code 491 is for insufficient secondary air injection flow bank one.
There is a device that pumps fresh air into the exhaust system to lower emissions. The sensor that measures air flow is telling the computer the air flow is below standard.
The system would need to be tested.

P0491 Secondary Air Injection System (Bank 1)
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car key programmer

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.

P0410 - SECONDARY AIR INJECTION (AIR) SYSTEM
P0491 - SECONDARY AIR INJECTION (AIR) SYSTEM INSUFFICIENT FLOW (BANK 1)

Secondary air injection (trademarked as Air Injection Reactor) is a process where fresh air is injected into the exhaust system to allow for a fuller combustion of exhaust gasses.

The possible causes are:
SAIR pump low or now air flow
SAIR bypass solenoid leaking/blocked or stuck open/closed
SAIR diverter valve leaking/blocked or stuck open/closed
SAIR air hose restriction
SAIR vacuum hose restriction or leaking

Check to make sure your air filter isn't dirty - and replace if needed. Otherwise I would suggest having your local trusted auto repair facility diagnose and repair the issue. A scan tool will be needed to properly diagnose the issue.

P0491 Secondary Air Injection System (Bank 1)
This code is not fuel injection but air injection, replace the secondary air injection pump.