I had a 410 last year and fixed it myself. no problem it was the vacuum switch that controls the air valve. It came up again this year, and I thought I had it. the brushes were gone in my pump so I replaced it. It runs when it is supposed to, for about one minute at start up. But I still get the code. Just a recap of what I have done between this year and last.
1, new Vacuum switch
2, new relay, and fuses
3. new pump
4. replaced the car side of the plug for the pump.

I know the check valves are bad,( I was getting an exhaust leak through the pump when the pump was supposed to be running) but don't know if they will cause the code to set since they were bad last year and I made it work. the air valve is not new but I assume it is working because of the previously mentioned temporary leak.

my guess is that something is clogged, between the pump and the manifold. I am tempted to replace the check valves and the air valve, but I am nearly broke and don't want to throw unnecessary time and money at it.

One thing I would like to do is a backyard version of step 3 of the troubleshooting flow chart using torque, but I don't know the command to command the pump on, does anybody know this?

 

Sorry, Torque cannot command the A.I.R. pump on. I have it and its very nice and useful app and I like it a lot (go to it first for everything) but it just can't do that (just like it can't display cam retard or do the crank learn or do the injector balance tests). I do use HP Tuners VCM and it has a lot of this functionality with turning things off/on (for example I recently commanded my TCC to lock up as a test of it's functionality), but it is pretty pricey in comparison. On the other hand, it had nothing for me for 4WD diagnosis or monitoring. Tech 2 is the only way I know to go straight through all the factory charts as written.

Post the flow charts and wiring and maybe we can figure out an alternative way to do the same functional test.

 

Ouch, wouldn't this ruin the new pump you put on, if exhaust was back-flowing through it due to a bad check valve?

 

https://blazerforum.com/forum/diagno...plained-35146/

I'm going to go warm it up and then stop and restart it and see what he o2 voltages are. not sure if that is the same though.

 

I suppose it could introduce moisture and freeze it up, but the old one never froze up, I am guessing the air valve keeps the exhaust out when the pump is off, and the air flow keeps it out when it is running. It is on my to do list, just not right now unless it is necessary.

 

So now I know why you have to command it on to run that test. the pump doesnt run if you are already warmed up. The o2 voltages did go up after the pump went off. but I dont know what that means, regarding my problem.

 

If you want to know when the PCM is commanding the AIR pump on, you can monitor circuit 78 at connector C2 pin A (red) with a test light or volt meter. At this point you should also have voltage on circuit 415 at connector C1 pin A (pnk/blk) if the fuse is good for the AIR solenoid.

If PCM is commanding AIR pump on, it should open the solenoid and output air from the port attached to the hose that leads to the exhaust manifolds. Maybe you can check it functionally this way. Stick a piece of heater hose on it, direct it into your mouth (seriously), and watch the test light or volt meter for the PCM commanding the pump on when someone else starts up the vehicle. It will become apparent if it is out-putting air.

Only time you can be sure the air pump will be commanded on, is initially after a cold start. If you make it through the first couple of minutes with no PCM control signal, then something is wrong.

Also, there should be absolutely no exhaust coming back through the hose to the pump at any time when the engine is running.

P410 means both banks affected equally so unlikely to be O2 sensors, manifolds, etc and places the problem in something that both banks share.

Maybe that will help?

 

it is running at the beginning of a cold start for about a minute. there is suction at the inlet hose, but it doesn't seam very powerful, but I also don't know how much it should be.

 

Is #3 opening and allowing the air from the pump to reach the exhaust manifolds. As I understand it (per step 15 in procedure you linked to), this requires 10" min of vacuum to come from the engine through #4 (#4 solenoid is controlled by the PCM). So disconnect outlet for #3 and check flow with your finger during cold start. If none, put a vacuum gauge on the small vacuum line leading to #3 and watch to make sure it is getting the vacuum signal. If anything was damaged by exhaust coming back through a bad check valve, #3 (a plastic piece) is first in line before the pump itself.

If only these problems could be diagnosed and all possible problems clearly identified enough to give a repair quotation with the push of a button using an Autozone scanner (like MilwaukeeWoman1 thinks)!

 

thanks, Im debating getting a vacuum guage, or just replacing the air valve and check valves. if i do that everything will be new(ish) except for the plumbing and wiring. so if that fails, I'll take it to someone who can do the diagnostic by the book.