I have two enging codes. What to check
 

I have a 410. Secondary intake code

The P0410 code refers to the emissions system. The AIR pump puts air to the exhaust to lower emissions. It takes in outside air and pumps it through two one-way check valves into each bank of the exhaust.

And a 1411. SAI System Incorrect Downstream Flow Detected


What the hell do I check here?

P0410 air injection pump was not triggered
P1411 air injection pump is not working.

Actually...

p0410 SAI system, bank 1 below limit
p1411 SAI system, bank 2 below limit

This could be anything in the SAI system. Start with verifying that the air pump is turning on during cold starts. Next, check the changeover valve since it's easy to get to. After that, I'd check for vacuum leaks. Moving down the line, check the electronic changeover valve and check valve (alternator must be removed to get to them - depending on the year of your car, you may have a combination valve that has both the changeover and check valve in one unit).

ACTUALLY: Taken directly from the OBD II manual for the car, Page 410-2

"P0410 Secondary Air Injection signal implausible, cylinders 1-3 Fault condition: Secondary air injection pump is not triggered"

"P1411 Secondary Air Injection signal implausible, cylinders 4-6 Fault condition: Secondary air pump does not work"

How much do you want to bet that the air pump is working? :D

Why would you get an "air pump does not work" for only one bank? Clogged ports maybe, but other than that, you wouldn't. ;)

Many have had these codes (myself included) and it's almost always a bad changeover valve or a vacuum leak. I'm going by real world experience and don't care what some incorrect book says.

Either way, you use logic: these codes are triggered by incorrect voltage at the pre-cat O2 sensors (0410=bank one, 1411=bank 2), meaning that there is insufficient airflow at the indicated bank(s) during SAI cycle.

The codes say it is not working for either bank. And that "incorrect book" is the factory OBDII manual, written by the same guys that programmed the DME............................

It is also easy enough to find out if the pump is working or not.

I had the same problem and it turned out to be a huge vacuum leak.

the Vacuum reservoir failed on my 2003. I also had the check valve that inserts in the manifold to source the vacuum fall out.

So I had very little vacuum to run the SAI system and the other items actuated by this vacuum system.

Get a vacuum gauge. Insert it into the system with a "T" connector and see if you are getting 15 to 20 " Hg reading. I was getting close to nothing in vacuum.


Next test the reservoir. Hook a hand vacuum pump with gauge directly to the reservoir. See if it will hold vacuum. If not replace the reservoir......they cost about $20.00. The reservoir is made in 2 pieces and glues together. It is a common failure that it becomes unglued. Mine would hold no vacuum. You do not have to un-mount it to test it. Use long needle nose pliers to remove the rubber fitting and attach a hose from the tester.

Look at all the vacuum lines. The lines are plastic with rubber connection pieces. the rubber ages and cracks. I have replaced as much of the Porsche vacuum lines as I can reach with 4mm high temperature silicon hose.

There are several good vacuum posts on this site.

Keep us posted and ask lots of questions. Particlewave knows his stuff!! He helped me a LOT!!

UMMM I don't know about that source.....

BUT I do know that PARTICLEWAVE is right.

Fine, then listen to him and let me know how you make out. But the answer I gave to the original poster is correct.

Both points of view could be right. Check to see if the pump works. If it does, then look for a vacuum leak. My 01S had those same codes. I replaced the pump with a used one and they returned. Ultimately, a failed reservoir turned out to be the problem

My point was that the air pump could be working with those codes because there is no mechanism to tell the DME if the air pump is working or not.

The codes are caused by an incorrect voltage reading at the pre-cat O2 sensors during SAI cycle. The cause of that is insufficient airflow from the SAI, which could be air pump, changeover valves, vacuum or clogged ports.

Happy hunting! :)

I don't know if this helps, the mechanic who checked the codes cleared it. They didn't come back until about 2 weeks later and I drove the car everyday

What year car is this for? I've heard some of the codes can differ between different DME revisions.

2000 986 Boxster base

Not these codes. ;)

Yup - pulled out my DME 7.8 book and there they were.

Fuzzuki - Here's what I did to kill the dreaded SAI code.

http://986forum.com/forums/performance-technical-chat/65985-need-professional-help-diagnosing-durametric-data.html

To cut to the chase on the thread, the SAI comes down to a blower moving air through the heads directly into the exhaust manifold ahead of the cats.

If the air does not appear on cue, you get the codes.

This occurs at a cold start when the temp is below about 70F, but it also occurs while you are stopped idling after going down the road as part of a drive cycle check. Sneaky.

So, what to check?

Vacuum leak as already noted. The valves are driven by vacuum, lose that, and you get the codes

The valves may not be operating - change them - it's a booger.

Under the rear trunk liner that covers the left rear fender there's a big honking green fuse . Check that fuse. If it is blown there's likely a vacuum problem that helped it blow, the blower fan was dead headed. Mine was blown because my changeover valve was not opening due to lack of vacuum - all that is in the string above.

There are also computer wires that run the solenoid valve for the changeover valve - if they are damaged then the system will fail, but that does not seem likely.

Best of luck!

That fuse was good.
Will check further into this issue on the weekend.

I checked. My blower motor is not running.

I just put a glass window top on.
Its really hard to get the top into the correct position to gain access to the motor??

Is there an optimal position for this?

I just replaced my stock roof with a glass window with a replacement roof with a glass window. The new window is a little bigger and I have no idea how I'll get at the engine now. Access is cut in half with the new top when in the service position. Oh well, I just hope things hold together.

You can power your blower motor directly off the battery by pulling the fuse and running a large gauge wire from your battery positive to the fuse holder I pulled the fuse and made the connection at the back of the fuse holder. I did not want to power the upstream part of the circuit even though it would be open, just didn't know what I might be sending power to.

If the fan runs at that point you just eliminated that part of the system (fan and associated power wiring) from the fault tree.