Where is the secondary air injection system?

The secondary air pump must draw in ambient air and inject it into the exhaust gas manifold downstream of the exhaust valves. If the air is drawn not from the intake area but directly from the engine compartment, a separate air filter is built into the secondary air pump.

What causes a secondary air injection pump p0491?

Potential causes for a P0491 may include: A fuse or relay for the secondary air injection pump may be faulty A leak in the hoses/piping between the secondary air injection pump and the Combi or secondary air injection A sensor for the secondary air pressure may be faulty

What are the symptoms of a p0491 engine code?

Symptoms of a P0491 engine code may include. Potential causes for a P0491 may include: A fuse or relay for the secondary air injection pump may be faulty A leak in the hoses/piping between the secondary air injection pump and the Combi or secondary air injection A sensor for the secondary air pressure may be faulty

Why is my secondary air injection pump not working?

A fuse or relay for the secondary air injection pump may be faulty A leak in the hoses/piping between the secondary air injection pump and the Combi or secondary air injection A sensor for the secondary air pressure may be faulty The secondary air injection port in the cylinder head may be plugged with carbon

What to do if your vacuum leak is p0491?

Solutions for P0491 may include: Repairing or replacing any damaged vacuum hoses or fittings which could be causing a vacuum leak Technicians note that this malfunction almost always occurs in times when the weather is cold.

What happens if air pump and check valve are faulty?

After about minute, the system turns itself off. If the air pump and check valve are faulty, they are normally easier to replace; however, many of the vacuum lines are under or behind the intake manifold. This makes them difficult to reach in most cases.

Where is the secondary air injection system?