Hello Hummer community,

I have been cursed with this code for a while now. After working hard to get the ol girl up and running mechanically and resolving all previous misfire codes and maintenance items which were pending, this is the LAST code that’s left for me to have a clear dash again.

I understand that mechanically this problem will not affect me, although I would like to resolve this code for two reasons:
1. To know if there’s an actual problem.
2. My self diagnosed OCD wants the light to be off.

I see that this issue was discussed prior but I was not able to find a final solution. https://www.hummerforums.com/forum/h...problem-28464/

Okay so here’s what I’ve done:
1. Air pump hoses (good)
2. Air pump (checked with a 12v source)
3. Fuses (I think I check all the ones based on the diagram on the fuse box)
4. Relays (unsure of their location, please help)
5. Check Valve (not sure what to check or how to check)

Thanks!

 

relay is mounted on the back of the intake

 

look up the check valve part for your year and engine on one of the auto parts site to get a picture of what it looks like then find it on your truck

 

The check valve(12619109) is mounted on the side of the engine above the exhaust manifold, failure would most likely clock a P2431. Start with a basic test on the P0411, on a COLD engine, start up, and feel the pump to verify it is operating.

 

Bronxteck, the check valve is on top of the motor, where hose #2 connects to. So finding it is not a problem, its how to diagnose it properly that I do not know much about. Although, Hummerz stated that a failed check valve would warrant another code.

Hummerz, the picture of where the relay was really helpful! I will do the test as you suggested and report back.

 

Hummerz, I had a friend turn on the car while I had a hand on the Air Pump. I could feel the pump turning on normally. This means that the relay works and the air pump is receiving proper power and grounding from the ECM.
At this point, I believe the only component I have not diagnosed/tested is the check valve. Not sure if there is any way to diagnose these or just replace? Around $150 for a replacement from RockAuto.

 

well before spending all that money maybe you should get the ECM software updated first like the tsb dictates.

 

Check for air coming out of the solenoid with the pump and solenoid commanded on or listen for air flow at the tailpipe.
If there is air coming to the solenoid but not through it when energized, the solenoid is defective.
The AIR solenoid is a normally closed solenoid. When the AIR solenoid is energized, the valve opens and air passes into the exhaust system.

 

So I’ve been plagued with this for a while now. I just replaced my Valve cover, intake manifold, and plugs to resolve a misfire and oil leak in spark plug tube. With the urgent issues resolved, I thought I’d give it another try. So far:
1. Replaced Air Pump(confirmed it works with 12v)
2. Replaced Relay (confirmed it works checking resistance after switch is active)
3. Checked hoses (all good still, no leaks or breaks)

I followed up with dealer about resetting the BCM/ECU and they said it would be $149.. *rolling eyes*

This time around during diagnosis I do NOT see the air pump turning on at all. So I put a voltmeter onto the connector for the air pump and got 0volts when I turned on the car. This leads me to believe that the relay is not getting grounded properly to complete the circuit to power on the air pump.

Now the question here would be what do I do next? Lol is there a way for me to manually ground the relay to test if the pump will power on?

 

Actually I just tested the ground by adding a wire to the ground pin and installing the relay on top of it so the wire is in place where it should be for the ground but also exposed for me to manually ground. After that I grounded the wire on the battery and turned on the car. Lo and behold, the air pump was blowing full force now.

I’m not getting the P0411 code anymore after clearing, I’m still getting “P2432: Air system air flow/pressure sensor circuit low bank 1”. It may be because I’ve turned the car on a few times to test and it’s too “warm” to turn on the secondary air pump. I’m going to wait an hour and try again.