Hey guys .... its been a while since i checked in... my hummer has been doing great ever since the immobilizer problem with the aftermarket alarm, anyways a few days ago the CEL came on.... i checked it with the scanner and it read code p0411, nothing seemed serious so i just erased the code with my OBDII scanner. well a few days later i reread the CEL because it came on again and it was the same CEL code p0411 ive searched this forum high and low and seemed to have not found a fix for it.... i already checked the fuses in the bay for the air pump and none where blown. i also checked the hoses that connect from the airbox to the airpump and they seemed pretty snug is there any other possible reasons why its throwing this code?

my hummer is a 2008 H3 with about 13,6XX miles on it... i usually only take her out on sundays

any help would be much appreciated

 

not to sure what that code stands for, have you tried calling a dealership for a definition? the dealership also told me if the engine light is not blinking then your ok, meaning that it's not doing damage to the vehicle. they said once it starts to blink shut it down and call us for a tow

 

P0411 Secondary Air Injection System Incorrect Flow Detected


What does that mean?

Secondary Air Injection is an emission control that uses an air pump (either electric or turned by the drive belt) to move fresh air into the exhaust manifold(s) or exhaust ports when the engine is in open loop and pre-catalytic converter when in closed loop. This reduces hydrocarbon emissions (HC), Carbon Monoxide (CO), and oxides of Nitrogen (NOx). This fresh air helps convert Carbon Monoxide (CO) into Carbon Dioxide (CO2) and Hydrocarbons (HC) into water vapor (H20).
A check valve is located in the air supply line to keep exhaust gasses from flowing into the pump. A cutoff valve that controls the airflow may be vacuum controlled or electrically controlled. When the powertrain control module (PCM) activates the valve, vacuum travels to the cutoff valve to open it and allow fresh air to flow. Some systems may have only a check valve and the flow may be regulated by a electromagnetic clutch on the air pump (similar to an A/C clutch).
Under hard acceleration, the air pump will be deactivated to prevent backfiring in the exhaust. To self-check, the AIR system will be activated by the PCM and fresh air would be routed into the exhaust system. The oxygen sensors would sense this fresh air as a lean condition and the short term fuel trims would begin to move in the positive direction to compensate. The PCM expects to see this happen within just a few seconds during the self test. If it does not see the short term fuel trims rise, then the PCM interprets this as a malfunction in the AIR system and a code will be recorded.

Symptoms



Symptoms of a P0411 DTC may include:

• MIL (Malfunction Indicator Lamp) illumination
• Backfiring in the exhaust under hard acceleration
• Engine running rich (This is counter-intuitive. See explanation below)
• Squealing belt

Causes



Potential causes of a P0411 code include:

• Damaged or missing check valve
• AIR pump intake port plugged/damaged
• AIR pump clutch malfunction
• Holes or damage to exhaust components

Possible Solutions

If you have access to a scan tool, with KOEO (Key on engine off) command the AIR pump on. It should activate. If it doesn't, remove and inspect the AIR pump relay for discoloration/melting due to heat. Repair as necessary.
With the ignition on (engine off) check for battery voltage at the switched battery feed to the relay and the relay control circuit. If either of these isn't present, inspect circuit for blown fuse or open/short in the wiring. Repair cause of short and retest. If they are both present, jumper the battery feed to AIR pump feed circuit using a fused jumper. The pump should activate. If not, check for power and ground present at the AIR pump when jumpered. If there is no voltage/ground present at pump repair open in wiring harness. If voltage and ground is present, but pump still does not run, suspect a bad AIR pump. If after jumpering the AIR pump feed circuit the pump activates then the problem is likely the AIR pump relay. Replace and retest.
If the scan tool activates the AIR pump, with KOER (Key on engine running) activate the AIR pump solenoid valve on and see if there is vacuum to the cutoff valve. It should have vacuum present to open the valve. If there is no vacuum present, check the AIR pump's vacuum solenoid valve for vacuum supply from the manifold. If there is vacuum present then the vacuum solenoid is likely bad. Replace it. If there is no vacuum present at the supply to the vacuum solenoid, check for a plugged or damaged vacuum line or plugged vacuum port. But if there is vacuum present at the cut-off valve, shut the engine off and using a vacuum pump, apply vacuum to the cut-off valve and see if it holds a vacuum and that air flows through it when vacuum is applied. If it doesn't hold vacuum or the valve doesn't flow when vacuum is applied, replace the cut-off valve. If the cut-off valve works properly, inspect the check valve for obstruction or to see if it's missing. Replace as necessary.
Check the steel line to the exhaust catalyst as well as the exhaust ports for damage or holes that could give a false reading

TSB

PIP4361B: Intermittent SES Light due to DTCs P013B and or P0411 DTC - Reprogram ECM - keywords calibration cold controls engine engineering investigation lamp light program recalibrate reflash ses start - (Jun 12, 2008)

Subject: Intermittent SES Light due to DTCs P013B and/or P0411 DTC

Models: 2008 Chevrolet Colorado
2008 GMC Canyon
2008 Hummer H3
with 2.9L Engine (RPO LLV)
or 3.7L Engine (RPO LLR)
2008 Chevrolet Trailblazer
2008 GMC Envoy
2008 Saab 97x
with 4.2L Engine (RPO LL8)

This PI was superceded to include DTC P013B as well. Please discard PIP4361A.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
On rare occasions, an intermittent SES light may be experienced due to DTCs P013B and/or P0411.

Recommendation/Instructions:
If the SI diagnostics do not isolate a cause for this concern, reprogram the ECM with the latest TIS2Web calibrations and evaluate the concern. At this time, the latest calibration is titled "New calibration with diagnostic enhancements for DTC P0411." This calibration, or any that follow, is designed to address this concern. "

 

thanks hummerz!!!!! i will check all those things out,.... what luck i have with the 2008

 

hey everyone thanks for the help.... so i finally went ahead and tried to fix the problem myself yesterday, i pulled off the pump, checked the relay and checked the hoses for leaks.... everything seemed to work just fine.... i connected the air pump directly to a battery and it turned on with no problems, my only problem was i couldnt pull out the relay in the fuse box in the engine.. but a visual inspection it looks fine, so i put everything back and ran her for some reason when i put it back i heard the air pump blow for the first time and i even drove her and no CEL came up. Now when i take her to get a lil gas the CEL went on again and its the same code. so my question is what do you think is broken? the air pump? or the relay? what could possibly cause the air pump to not on when i turn on my car?

 

I'm also having this problem. I hope this isn't considered necro bumping as the last post was one year ago. My 2007 H3 was just purchased from Florida with only 19k miles on it. Looks like new outside and inside. Can't see any reason the air pump wouldn't be working correctly but it never does run. I was hoping someone had found a common problem with these air pumps so that I can check that first.

I clear the code and it stays clear until the next cold start. The light comes on and the code returns.

If anyone knows where I can find the complete wiring diagram for the H3, that would be a big help too.

Thanks

 

http://schwarttzy.com/wp-content/upl...iring-2007.pdf


H3 Hummer

 

That's a great resource. Thanks...

 

Will re-programing the ecm solve this problem i tried every thing else !!!!!!!!!!!!!!!!!!!!!!