Need help with Air Pump (emissions)

I have a 2002 GP bought in NY state, it has a "secondary air" system, some kind of added emissions gizmo required in NY.

The code returned is 410, kinda useless, it just says there's a prob. in the secondary air system. I took it to a shop, they said it could be one of three things: the air pump, the air pump valve, or the air pump solenoid. A local dealer said "we replace a lot of air pumps", so I decided to bite the bullet ($200) and replace it. I did that tonight.

The Svc. Eng. light is still on, I believe it won't go away until there are a number of trouble-free cycles before it will go away.

Q - Does anyone know how the pump, pump valve, and solenoid work? The computer would obviously control when the air pump comes off and on. The pump is pretty simple - it pumps, or it doesn't. But what to the valve and the solenoid do?

I'm trying to understand the system. I don't really know if I fixed anything yet. Any details would be GREATLY appreciated !

You're one of the unlucky ones with a green state RPO NC8 which is the secondary air stuff.

You may need to let it complete a few drive cycles or have the DTC reset. If that doesn't work then there are other possibilities that may be causing the problem. The air pump injects air into the exhaust before or at the CAT convertor to further cut down on emissions since California LEV standards are strict. The valve is a one way valve which will allow the air to pass to the exhaust but not back where the air pump would get damaged. All is controlled by the PCM module. The solenoid is what turns on the pump when called into action.

There are two modes called active and passive that use the 02 sensor to test the secondary air injection circuits. If it fails you'll get a P0410 DTC.

In a worse case I heard that a bad CAT convertor can cause that problem or even a flaky 02 sensor. But I'd start with the easy which is resetting to see if the new pump fixed the problem.

Thank you SO MUCH for that detailed explanation!! I am getting a code 410.

The car has 142,000 on it, the cat went bad at 79,000 and was replaced under warranty, which was good until 80,000. Talk about cutting it close, huh?

Check this out - when I removed the air pump, about 1/4 cup of water came out of the line on the output side of the pump. I assumed that's a bad thing, but if it goes to the exhaust, it shouldn't hurt anything.

I actually live in PA and they don't test emissions or require this extra system where I live, but like a dummy I bought the car in NY b/c that's where the closest dealer is. NEVER AGAIN!!

On certain 2001 - 2002 GP models GM extended the CAT warranty to 120K or 10 years whichever comes first but you're out of that coverage with your mileage.

Here's a little more tech info on P0410.

Two tests are run by the PCM. Non-intrusive and Intrusive.

The non-intrusive test is run at startup in open loop mode. It looks for 02 sensor voltage above 598.96 millivolts for a rich time ratio of 1 but is failing. To pass the 02 sensor voltage must be below 0 mvolts for a lean time ratio of 1. Therefore, to fail the 02 sensor voltage is below 598.96 mvolts for a minimum of 5 seconds after the pump is turned off. Must have above 598 mvolts for 25 samples to pass.

In the intrusive test the air pump is turned on to force a change in the 02 sensor signal. The 02 sensor signal must be forced continuously below 73.785 mvolts for greater than 1.5 seconds to pass.

Also, GM has a TSB out covering a mod where a plastic shield is added because of the air pump was accumulating water. When the car warms up if any water is getting back to the exhaust system it should be vaporized.

Alot of use are happy we are not in green areas so no air pump circuits but for 2001 and up models it is quite common nowadays.

Good luck and let us know how it turns out.

OK, I'm finally getting somewhere with my 410 code and my air pump. Since this was such a pain to figure out, I figured I’d pass along what I learned.


My shop tech told me there are three things involved:
- the air pump (blows air)
- the air pump solenoid (kicks the pump on and off)
- the air pump valve (allows the pump air to blow into the exhaust, but prevents exhaust from being blown into the air pump)

He says when there’s a 410 code, it could be set by a fault in the solenoid or the pump, but not by a fault in the valve. The problem this creates is, let’s say the valve is bad, and exhaust is blowing into the pump. The pump will fail. You replace the pump, and it seems “fixed”, until the pump dies again from all the exhaust crud. This presents a dilemma of what part to replace.

I decided to replace the pump first because, according to the dealer, they replace a lot of them because they get damaged by water. Sure enough, when I took my pump off, water came out of the hose. Tonight I dismantled the old pump, not only was the motor was soaked, but there was also a lot of deposits and corrosion on it from the water. This sealed it in my mind – my pump failed because of water getting in it.

I saw no signs at all of any black crud from the exhaust. From this, I conclude my air pump valve is working OK.

When I installed the new air pump, the SES light was still on. I expected to hear the new air pump run, but it never kicked on. Uh oh. I took the car to the shop I use, they reset the SES light, and voila, when I started the car, I heard the air pump kick on. I don’t know why the pump won’t run when the SES light is on.

My repair tech reset my SES light twice before I replaced the air pump, and each time the SES light was back on within 50 miles. Now that the air pump is replaced, I’ve driven over 100 miles without issue. The air pump is working, the SES light is off.

GM has an ongoing problem with water getting into the air pump. They’ve tried to correct this with a shield of some sort, but that’s not too successful from what bnaylor has posted. They put the air pump way down in front of the front wheel, low in the fascia. It’s going to constantly get wet down there. Real dumb.

If I were troubleshooting this problem in the future, the first thing I’d do is remove the air pump and check for water, and/or soot. Water, and I assume the pump is bad. Soot, and I assume the air pump valve is faulty.

Hopefully some of this will be useful to someone.

thanks alot for the info i have a 2000 gp 3.8 liter i am having the same problem. i am going to take the pump out this week and check it out . thanks alot fot the input.

Glad I could help!

thanks alot for the info i have a 2000 gp 3.8 liter i am having the same problem. i am going to take the pump out this week and check it out . thanks alot fot the input.

Sorry but please check the date and do not resurrect old threads. Any thread over 3 months old will be closed in most cases. If you decide to update whatever your remedy/fix is be sure to do in your current thread addressing the P0410 DTC. See link below.

http://www.automotiveforums.com/vbulletin/showthread.php?t=711601