P0411...Please help

[bowtieboy12]

2007 cobalt 2dr 4cyl manual.

So last year I get p0411 and several other codes. I replaced the air pump and check valve, cleared the code and it was good. So it comes back recently, I replace the air pump and check valve again, still throwing codes. I read that the relay will blow if the pump is locked up. So I put in a new relay and clear the codes. CEL stays off for like two weeks. Was ready to get it inspected was waiting for secondary air monitor to go. Then CEL comes on. P0411 again! EVAP monitor incomplete now but secondary air monitor completed. I'm at a loss here. Any help or suggestions would be greatly appreciated. Thanks guys.

~Patrick

[bowtieboy12]

nothing?

[Levithan9]

Checking in identa fix...their are 78 confirmed fixes for your problem. Replace the AIR INJECTION REACTION SOLENOID.

Be advised...the solenoid malfunction may take out your new air pump.

Hope that helps.

If you need the diag steps, let me know.

[Tech II]

I believe the check valve and the solenoid are both the same thing......they are one unit.....

There is a pressure sensor incorporated, I think, into the solenoid/check valve....

So you have replaced the pump and check valve twice, and a relay.....that's called parts changing, not diagnosing......

Did you check the pump, both times before replacing, to see if they worked? Did the pump, on both occasions when you replaced them, did they have water in them? I know on other vehicles, there have been TSB's for replacing and repositioning the inlet hose to the pump, to prevent water intrusion....this can lead to freezing in the pump, and causing a fuse to blow....

Basically how this works is, one of the main inputs to the PCM for pump operation, is the coolant temp sensor......depending on coolant temp, will determine if the pump comes on, and for how long, when the vehicle is started.....P0411 sets when no flow is detected......there are two inputs of data to the PCM for this.....one is the pressure signal from the check valve assembly.....the other is the O2 sensor......on a cold engine, the O2 sensor will initially tend to run rich or fluctuate rich/lean.....however, with that air pump on and the the check valve open, you will get a lean condition from the O2 sensor....

Possibilities....there are two relays, one for the pump and one for the AIR solenoid(check valve assembly)......we could have a bad harness or connection to the the pressure sensor in the assembly.....could be a bad ECM/PCM.....there could be an obstruction between the pump and check valve, or between the check valve and and the exhaust.....basically you need a Tech II scanner to command the pump on, and the valve open, and see a corresponding change in the pressure data and also in the O2 reading, to see if the system is functioning....