I need help on exactly what these codes mean.

P0400: PCM has determined that a malfunction exists in the exhaust gas recirculation flow.

P0410: Secodary AIR Injection system malfunction.


All help and/or opinions greatly appreciated.

 

EGR is bad, unplugged, blocked or something

and

Air pumps bad, unplugged, blocked or something

 

Anymore help out there? Looking for more info.

 

How much more info do you need? He told you what the problem is.

 

I got the 400 code when I put my headers on beecause there is a vacuum leak where the manifold flange and the AI tube is. I have to get a new flared connector. Did you put headers on your car or modify it in any way right before your codes came up?

 

did your Air Pump get replaced under the GM recall?
They had an emissions recall on some 95's all 96 and 97 LT1 Air Pumps. They had an electrical fault which caused them to short out.

When my EGR went the car ran really rough and stumbled is this happening to your car?

Try pulling it off its on the rear of the intake manifold and cleaning it with brake or parts cleaner. PITA-BTW

 

check the AIR pump fuse in the fuse block under the hood. it will be a 20A fuse. if its blown (and you havent had the recall done), then the air pump prolly has some water in it. if so, then it is junk. I have a few air pumps left over from doing the recall at work(I saved the good ones just for occasions like this). so let me know and I can give you one.

as for the EGR code, they usually will get stuck (open or closed) and not work. the pcm expects the idle to change when it commands it on, thats how it knows if the system is working. for that, you need to reach back there and push on the plunger of the valve while the eng is running. it should start running poorly and chopy if the valve is opening like it should and its not clogged, then go back to smooth after you let it go to make sure its not sticking open. or the better way is to use a hand vacuum pump to open and close it.

chris

 

Thanx for all the advise. IrocSS85 I'm going to check that out on lunch and take you up on the offer. How much?

 

The last 2 P0410 codes I got were due to bad check valves in the air system.
It's a one way check valve. Remove then and try to blow through. If it is blocked, no biggie. They're about 15-20 bucks.

 

I had the codes checked again and the EGR code was gone. For the AIR pump I checked for a fuse and found a relay. I had the code erased and changed the relay, now I have to wait and see if it pops back up again

Thanks for all the advise I'll let you guys know in a day or so.

 

Thought I was home free but the code came back IrocSS85 is that offer still available?

Kevyn how do I remove the check valves, and what am I looking for?

 

There's a link below showing the check valve location.
It happens to be a pic of my old ls1 car but they're about the same on a LT1.

You will need a couple large wrenches to remove the check valve from the tube which connects it to the exhaust manifold. I used two big crescent wrenches and some penetrating oil to remove them.

In the pic, the passenger side valve was replaced and it still looks new.

It should flow air freely in one direction and not permit flow in the reverse direction. In my case it was blocked completely.

A month later the other one failed. I should have done both at once. I think I paid 16 bucks for the valve. Hopefully it will be something simple (and inexpensive) like this.

http://www.imagestation.com/album/?i...5402973&idx=27
Click on pic for a bigger one.

 

yeah, I got the air pumps here. email me if you need one.
chris