DTC P0410 Secondary Air Injection System Understanding, Testing and Repairing

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BMW Technical Information System
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This DTC P0410 code references a problem in the secondary air injection system. Historically it was called the AIR system, which was an acronym for Air Injection Reaction.  If we dissect this historical name we can learn some about what its intended function is. Air Injection is pretty simple to understand, it simply means that we are pumping or injecting air into something. Reaction is a little more complicated unless you understand that Catalytic Converters are really two catalytic converters in one. The front half is the “Reaction Catalyst” and the rear half is the “Reduction Catalyst”. Those vehicles that require extra air for proper operation of the reaction catalyst during times of heavy load are the ones that Secondary Air Injection Systems are installed on.

During these periods of heavy load, the PCM grounds the power relays that control power to the secondary air injection pump and the one way check valves. How the PCM determines that the system is not working, is during those times of heavy load / high fuel requirements it monitors the voltage from the pre catalyst Oxygen (HO2S) sensors.  If those sensors are generating voltages that correspond to lean conditions while the PCM applies the ground circuit for all the secondary air injection components, then the PCM accepts this that the system is functional.

Simply assuming that the AIR system is malfunctioning and replacing components is the quick way to misdiagnose this system. The first thing to do is research the factory Technical Service Bulletins (TSB) for your vehicle and see if the manufacturer has issued any related to your car. If there are TSBs you should check these first as they will usually guide you in what the manufacturer has seen from its dealer organization. However as the vehicle ages, the manufacturer information should be considered as part of your overall diagnosis and not all of it. 

Before any serious inspection of the secondary air injection system or its individual components should be attempted, there should be a basic diagnostic to verify engine operation, exhaust leaks in front of the HO2S sensors and the performance of ALL the HO2S sensors including the post catalytic converter sensors.  This can be performed very easily with a Scan Tool. A HO2S sensor that is already locked lean or lean biased or is simply bad could not be used to accurately diagnose whether the AIR system is functional or not.

If everything checks properly then proceed with the Secondary Air Injection System (AIR) diagnostic. This includes check for power to the pump, and valves, relays, and checking the pump and valves themselves for function as well as failure, and checking the hoses for tight fit. For proper testing, you should consult the manufacturers’ factory service manual, or a Product Service Training book such as PST # 16016.05-1 Computer Command Control (C3) Fundamentals 85.

An enhanced scan tool is not needed for any of this testing as it can be performed by simply understanding the system, how to engage its operation manually. Monitoring the HO2S sensors with a good generic scan tool such as the 2X80S USB Scan Tool and an automotive diagnostic software program such as OBD 2007 or Scan Master can easily determine the reliability of data.

For The Professional

If the Secondary Air Injection System (AIR) has been non functional for an extended period, remember to test the HO2S sensors and the reaction catalyst for damage before releasing the car back to the customer. A long test drive is needed to thoroughly warm up the Catalyst to perform the follow up testing. Remember to compare the readings to your baseline readings to verify the repairs are complete.

If you have doubts, express them to your service adviser and have him contact the customer. Then place your comments in an appropriate place on the RO. If you fail to do this you may get a recheck later for a failed Catalyst and or a full set of HO2S sensors or both.

Fundamentals training book


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         Fix It Right The First Time!

Fortunately, everything you need everything you need to fix it right the first time is right here!

To access the sensor and data from your Engine Controller (PCM) you will need:

Professional Quality Scan Tool such as our 2X80S Scan Tool series.

Professional Quality Automotive Diagnostic Software such as OBD2 Spy, OBD 2007, or Scan Master.

If you understand how the systems were designed to work and how to test them, great! Otherwise you will need factory product service training manuals that will teach you and guide you through the diagnostic phase.

You might also need the manufacturer factory service manuals and data systems that provide specifications and details relative to your specific model.

Or aftermarket data systems such as All Data, Mitchell On Demand, Auto Data, Bosch, and others.

Everything is available here for you as a single source for all your needs. The aftermarket data systems are available in our members only area by direct shipment from the distributor at great pricing.

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