My check engine light came on and I took it to the parts store to get the computer read.

The error that came up is

Secondary Air Injection System Incorrect.

and the probable causes listed were:

1 - Faulty Air Solenoid Valve
2 - Faulty Air Pump Motor

Couple questions,

  1. What is the impact of this problem? I.e. will I hurt anything if I keep driving it?
  2. Can someone point me in the right direction to fix this myself? Don't mind doing it but MV maintenance is certainly not my area of expertise, to the degree that if I popped the hood I couldn't point out the air pump. I am pretty good at following directions though :)


Got home and popped the hood. Hoping someone can give me some direction here. My best guess, and this is a complete WAG, is that the air pump is the part I circled and that the solenoid valve is the part that sticks up and to the right out of the pump?

Please correct me if I am wrong. Also if someone could provide a cheapest to most expensive list of the potential fixes that would be much appreciated.

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3 Answers 3


The secondary air injection system is part of the emissions control system. Under certain operating conditions, the secondary air pump runs to bring fresh air into the exhaust system. It supports the proper function of the catalytic converter by making sure there's enough oxygen in the exhaust gas.

Will it hurt anything to drive the car? It could potentially lead to early failure of the catalytic converter, which is an expensive item on these VWs (don't ask me how I know).

How would one fix the problem? The "probable causes" you listed are a really good start. You should test the function of these two items.

First the easy way that requires some specialized tools: They can be checked with a specialized diagnostic tool like the VAG COM cable and software, which allows certain components like solenoid valves and motors to be to be tested by cycling power on and off to these components. This should be done with the engine off, if the component is working you will hear it operate. Solenoids should "click", and motors should "whir." The advantage here is you don't need to get your hands dirty, unplug anything, or even know where the components are located in the engine bay.

The harder way with no specialized tools is to locate the components in question and directly apply power to them with a length of suitable wire, again listening for a click or a whir.

Other possible causes would be a break in the plumbing of the secondary air system or a connector that popped loose.


What you have circled is the mass airflow sensor, which has nothing to do with the secondary air system. If I recall correctly, the secondary air pump is below the engine, on the front side, slightly to the left (drivers side) of the centerline.


Secondary air pump is located below the engine to the right. The combi valve is located to the left. There are a pair of black air hoses in between. The combi valve costs roughly 180€ and the air pump 430€. The secondary air pump manufactured by Pierburg (OEM) for VW is known to fault. The early models of the fan enclosure is using rivets instead of bolts. The rivets will not last and cause leaks and pressure leak, which causes the OBD II test to fail. Current replacement pumps uses small screws/bolts to keep the enclosure tight.

In order to gain access to the pump you have to remove 4 screws below the engine with the plastic splash shield. The pump is fastened to a bracket with 3 10mm nuts. Detach the electrical wiring to the pump along with the 2 airhoses connecting to the pump. Detach the air hoses from the secondary airpump to the air filter box and the combi valve. In order to remove the pump also the mounting bracket has to be removed. The bracket is fitted with 3 8mm allen-key bolts. In order to gain access to the 3 8mm bolts the following needs to be removed: 2 top engine covers, the secondary air pump vacum control system on top in front of the engine, the oil dipstick mount (yellow/orange) needs to be pulled off.

Fitting is reversal of removal. I would estimate that if you done the work before it can be done in 3 hours. If not, you most likely spend a day. You need at least, 6mm and 8mm allen key sockets with twisted headed grip to gain momentum, torx 25, flat headed screwdriver. 10mm spanner to complete the job.


The secondry air pump and system is provided on your vehicle to 'lean out' the exhaust in the cat, until the cat is hot enough to operate correctly. This usually lasts for only a couple of minutes on start-up and then the SAP is turned off.

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