P0411 and Engine Power Reduced - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 4 (permalink) Old 05-02-2017, 11:00 AM Thread Starter
Join Date: Aug 2016
Posts: 5
P0411 and Engine Power Reduced

Hello friends,
I've been having 2 issues from time to time. I am getting the P0411 Secondary Air Injection System Incorrect and Engine Power Reduced. This past weekend I cleaned the throttle body out spic and span. It had some grunge so I thought the problem fixed. Yesterday it happened again. Sometimes it will re-start and idle fine while other times it just does the same thing on restart.
When I check the codes I get the P0411 code only. Last night I took the throttle body off and inspected it. The sensor in built into the side of it so complete disassembly is was not possible for me at that time. I did take the clips off that hold the sensor and 6 (or 8 ) pin electrical connector and blew in some air from the compressor and sprayed some throttle body cleaner in there and air dried again.

This morning it started fine. So I tried to replicate the problem by shutting it off and back on a few times. It idled for about 10 seconds and then shut off. I checked the code and got the P0411. As usual when I get the P0411, I start it back up again fine. So my question is, do I have 2 separate issues or is the p0411 causing the reduced engine power (or vice versa). I believe every time I get the Engine Power Reduced, I also get the P0411 code.

I believe my throttle body is on it's last leg. I say this because I can now physically hear the butterfly or something else clicking on it when I turn the key. I mean loud enough to hear it inside the car when I never heard it before.

I've been reading some posts and got a diagram of the secondary air injection system from Coby in a post for someone else.

Looking for some advice before purchasing another throttle body or an air injection system.

Thanks my friends,

Last edited by Boujii; 05-02-2017 at 11:04 AM.
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post #2 of 4 (permalink) Old 05-04-2017, 12:09 PM
Join Date: Mar 2017
Location: Sacramento, CA
Posts: 20
I would start with the secondary air system first then go from there. I would think the 0411 would be causing the engine to go into limp mode but not 100% certain. Keep us posted.
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post #3 of 4 (permalink) Old 05-04-2017, 12:27 PM Thread Starter
Join Date: Aug 2016
Posts: 5
Yesterday I go out for lunch and bang, engine power reduced. So I hook up the scanner and got some new codes. Along with the normal P0411, I got a P0651 and C0700 P.

P0651 Sensor Reference Voltage 'B' Circuit/Open
I haven't quite found what the C0700 P is for yet. But it's not the C0700 Level control accessory inflator switch circuit high.

I found a youtube video explaining
. Though I haven't reached the no crank problem yet.

It would appear the bad air pump would not supply the 5 volt which is what triggered the P0651 code. I'll have to take it off and inspect it. The guy in the video was unsuccessful at just cleaning it out and had to replace it.

I am still not so certain the cause for the P0411 SAI code. It may be a problem on it's own or caused by the bad air pump. I haven't researched yet if the Secondary Air Injection uses the same air pump.

Edit: It appears this has both separate Air Pump and Secondary Air Injection pump. Strange that I would get codes for both pumps.

This morning it does the same thing and only codes for the P0651 and not the 0411.
I am going to pull the main air pump off this weekend and take a look at it. I'll probably tackle the secondary air injection pump as well but I don't think that is the one causing the reduced power. Generally when I get the p0411 it'll stall after 10 seconds after start, but start right back up without an issue.

I am beginning to think they are two separate problems since they both have separate pumps. But hey, what do I know lol. In any event, we'll see what happens after I remove the main air pump and inspect and test it.
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Last edited by Boujii; 05-04-2017 at 12:29 PM. Reason: Bold
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post #4 of 4 (permalink) Old 05-07-2017, 12:34 AM Thread Starter
Join Date: Aug 2016
Posts: 5
So today I try to address the P0411 and P0651 codes resulting in stall and engine power reduced.
After installing a transmission in my GMC Jimmy and an Oil Change on the wife's Town and Country, I lacked the ambition to pull the primary and secondary air pumps on the cobalt.

P0651 Sensor Reference Voltage 'B' Circuit/Open
I did look at the connector on the primary air pump and it looked fine. It seems to be a 2 wire (positive and negative) is the only thing I see electrical going to it. I am not sure where it is getting the Sensor Reference Voltage 'B' Circuit/Open from.

P0411 Secondary Air Injection System Incorrect
The secondary air pump has a 6 pin connector going to it. When I pulled the connector apart, the wiring harness connector end looked a bit wet. So I looked at the connector on the secondary air pump and it was quite damp. So I sprayed some throttle body cleaner in both connections and then cleaned the pins up. I then took a blow dryer and dried them.

The video I showed is a guy dumping water our of the primary air pump. However the secondary air pump had water in the connectors. So both of these may have water inside them.
I'll need to verify the primary air pump doesn't have another electrical connection to it besides the 2 power wires. At this point I am going to wait until something happens again. If either code comes back, I will take the pumps apart to see if there is water inside them. I am guessing these build up some condensation and just doesn't evaporate.
I'll follow up when either something happens again or I know something more definitive.

Thanks friends,
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