CEL: Error codes P0410 and P1411

[roadsterdoc]

CEL has lit up on three different occasions, all within a few minutes of starting the car. The first two times showed the above codes (scan courtesy of AutoZone). The last time the CEL went away on its own.

P0410 (typo edited) Secondary Air Injection System Malfunction

P1411 Secondary Air Injection System Incorrect Downstream Flow Detected/Manufacturer Auxillary Emission Control

So what is suspect here? Is it as simple as the diverter valves? Seconday air injection pump? Any help on what to do next is greatly appreciated.

Thanks,

Chris

2001 996TT

Edited October 30, 2005 by roadsterdoc

[ar38070]

These are the possible causes per the OBDII manual:

secondary air injection pump is not triggered

secondary air injection pump does not work

air supply lines restricted

electric change over valve does not funtion

air change over valve does not function

vacuum system leaks

The diagnostic steps are quite complicated and some need a PST2. I would check for loose hoses, air and vacuum leaks. After that I would take it to the dealer or to someone who has a PST2. I do not believe that this has anything to do with the diverter valves. This is an emissions control problem.

[Loren]

Hmm... my OBD II 7.8 DME manual says:

I don't show a P0411 for TT.

P1411 Secondary Air Injection System, Bank 2 - Below Limit

Check:

Check function of secondary air injection pump

Check relay

Check power supply for open circuit

Check ground line of secondary air pump

etc., etc. 12 tests in all.

You should be able to hear the secondary air injection pump at cold start up. If not, check the fuse - the air pump fuse is on the relay support panel behind the rear seats. It should be 40A. Then check the connections in the engine compartment.

[roadsterdoc]

Oops, my typo. The codes were P1411 and P0410.

Does the airpump make a groaning sound? If so, it's working. I'll check the fuse. Where is the SAI pump (and it's connectors)?

Thanks!

[Loren]

P0410 Secondary Air Injection System, Bank 1 – Below Limit

Now we know neither side of the engine (O2 sensors) are seeing the auxillary air pump output.

The sound of the pump sounds like a small vacuum cleaner to me. Usually it runs for a couple of minutes at start up.

The pump is located in the left rear most area of the engine compartment. Item 1 below (air injection system).

[roadsterdoc]

Checked the 40A fuse and it's intact. The hoses seem to be connected, but I do not think I could find them all. The electrical connectors are OK (BTW, I found the airpump on the right side of the engine compartment).

I can hear the airpump on cold startup, but it has a moaning/groaning sound. I guess that could be a bad pump, faulty valve or a leak. Looks like I'd better take it in to the dealer for a PST2 scan.

Thanks ar38070 and Loren for your help. I will let you know the results.

[roadsterdoc]

Just made a donation to the site. Thanks for such a great forum!

[roadsterdoc]

Late follow up on my original post:

One of the diverter valves was malfunctioning. I replaced both stock DVs with Bailey DVs and no more CELs. It is a simple fix and a common upgrade. I hope this helps someone else.

[jsmith996tt]

I am also having a new loud squeeling noise from the engine area on a 2001 turbo. Also getting codes p1411 and p0410. How is it possible for bad diverter valves to cause these codes.

Joel

[Loren]

I am also having a new loud squeeling noise from the engine area on a 2001 turbo. Also getting codes p1411 and p0410. How is it possible for bad diverter valves to cause these codes.

Joel

P0410 Secondary Air Injection System, Bank 1 – Below Limit

P1411 Secondary Air Injection System, Bank 2 – Below Limit

Possible fault cause

- Secondary air injection pump is not triggered

- Secondary air injection pump does not work

- Air supply lines restricted

- Electric change-over valve does not function

- Air change-over valve does not function

- Vacuum system leaking

Check to see if the air injection runs at cold start up and look for loose hoses.

[jsmith996tt]

thanks for the information. I have one question, how much vacuum should there be at the line comming from the vacuum Reservoir. There doesn't seem to be enough to operate the air valve once the electric valve opens.

thanks,

Joel

[tsandfor]

Loren,

Thanks for the help. My Secondary Air Pump just stopped working in my 99 996 67k miles. I followed your advice to check it out. Put 12 V and ground directly to the pump leads---was OK. Then tested relay (the one linked to the 40 amp fuse behind the left rear seat).--was OK. The fuse was OK. Put 12 V to post 30 on the relay--fan turned on. I think I had a bad fuse or poor connection on the fuse B4 in the panel near the driver's left leg. I tested OK with an ohmmeter, but would not work in the car. Changed fuse--all is well.

I'll be sure to donate.

Tim Sandford

Hmm... my OBD II 7.8 DME manual says:

I don't show a P0411 for TT.

P1411 Secondary Air Injection System, Bank 2 - Below Limit

Check:

Check function of secondary air injection pump

Check relay

Check power supply for open circuit

Check ground line of secondary air pump

etc., etc. 12 tests in all.

You should be able to hear the secondary air injection pump at cold start up. If not, check the fuse - the air pump fuse is on the relay support panel behind the rear seats. It should be 40A. Then check the connections in the engine compartment.