Following.... I have this code too. Mechanic said a vacuum hose came off and that caused it. But it has since returned.

 

The pump is only used for a few minutes a after a cold start to pump fresh air into the exhaust system. Once the catalytic converters are heated to a certain temperature, the pump is shut off as it is not needed - the cats can now do their job.

Here's a document explaining the "function chain":

https://benzbits.com/DTC/P0410.pdf

There are procedures in SDS to actuate the pump and check it. If the pump is coming on and shutting off when it's supposed to, then it might be that the pump is weak and not supplying enough fresh air for the O2 sensors to register.

 

The pump is only used for a few minutes a after a cold start to pump fresh air into the exhaust system. Once the catalytic converters are heated to a certain temperature, the pump is shut off as it is not needed - the cats can now do their job.

Here's a document explaining the "function chain":

https://benzbits.com/DTC/P0410.pdf

There are procedures in SDS to actuate the pump and check it. If the pump is coming on and shutting off when it's supposed to, then it might be that the pump is weak and not supplying enough fresh air for the O2 sensors to register.

Rodney,

Thanks for your information. I do not get the P0410 code at start up. It comes on after the vehicle has been driven several miles and is well warmed up. It comes on when the car is warm and idling. I have checked the pump at initial start up and always found it working and shutting down in about a minute. Since the CATS are hot when the code shows up could the problem be a bad O2 sensor and not the secondary air pump. I guess either way its a trip to dealer or someone with a SDS.

Thanks again for your input.

Alan

 

I think the only reason it comes on after driving a while is because it takes two consecutive start/fault cycles to trigger it. It's probably coming on after the second start, but it may even wait for the O2 sensors to heat up before illuminating the MIL. I guess it could be a bad O2 sensor that reads low. You really need to get the underlying MBZ-specific DTC and not just the generic OBDII code. if it's P2003, that indicates that the pump is not operating, which could be a weak pump or the changeover valve malfunctioning (it is vacuum operated). If it's P2028 or P2029, then that is engine bank specific, which is possible an O2 sensor issue.

You might want to invest in a good scan tool that can read your car's proprietary systems. A generic $25 OBDII scanner won't do this. There are some fairly affordable ($100 or so) tools that will do this such as the Autel DiagLink, iCarsoft (i980, MB-II v 2.0 or v3.0) and the Foxwell n510 Elite. There may be others, too. Just look for ones advertised as reading "all systems" and for Mercedes-Benz. This way, you can read and reset codes for yourself without paying the shop. There are many people in the forums that, given the proper codes, can give you some direction.

If you do decide it needs professional help, you might be better off finding a local MBZ specialist indy shop rather then the dealers. Dealers are stealers!

 

I think the only reason it comes on after driving a while is because it takes two consecutive start/fault cycles to trigger it. It's probably coming on after the second start, but it may even wait for the O2 sensors to heat up before illuminating the MIL. I guess it could be a bad O2 sensor that reads low. You really need to get the underlying MBZ-specific DTC and not just the generic OBDII code. if it's P2003, that indicates that the pump is not operating, which could be a weak pump or the changeover valve malfunctioning (it is vacuum operated). If it's P2028 or P2029, then that is engine bank specific, which is possible an O2 sensor issue.

You might want to invest in a good scan tool that can read your car's proprietary systems. A generic $25 OBDII scanner won't do this. There are some fairly affordable ($100 or so) tools that will do this such as the Autel DiagLink, iCarsoft (i980, MB-II v 2.0 or v3.0) and the Foxwell n510 Elite. There may be others, too. Just look for ones advertised as reading "all systems" and for Mercedes-Benz. This way, you can read and reset codes for yourself without paying the shop. There are many people in the forums that, given the proper codes, can give you some direction.

If you do decide it needs professional help, you might be better off finding a local MBZ specialist indy shop rather then the dealers. Dealers are stealers!

Rodney,

Thanks again. I have Foxwell 530NT scanner with Mercedes specific software....not that I know much about what to do with the info! I will check vacuum lines. Can you point me too what the change over valve looks like and where it is located.

I appeciate your comment on Benz dealers. I will try to find local shop that is competent in MB work.

Here is picture of scan tool message.

Alan

 

Code P0410 is the result of the Engine Control Module (ECM) indicating a malfunctioning Secondary Air Injection System. This happens when the O2 sensor does not accurately detect the changes in the O2 level of the exhaust while the air injection system is functioning.

If the pump is working, then this most certainly can be an O2 sensor problem.
Why your not getting an O2 code is strange.

Check the sensors on your foxwell and see how they are performing.
It will give you the min/max and the reading on your foxwell.

 

OK - that's what I needed! P0410 is a generic OBDII code that can represent one of three MBZ-specific DTCs (P2003, P2028 or P2029 ) The P2003 means that both banks are detecting low O2 levels which indicates not enough fresh air is pumped in. Since the pump is running, it's either the valve or a bad pump. Here's the valve:

https://benzbits.com/R230/SL600SwitchoverValve.pdf

 

Thanks Rodney! You're the best! Just what I needed.

Alan