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PCM code P0410 Secondary Air Injection Fault

12K views 18 replies 6 participants last post by  DevilleNut 
#1 ·
Guys,

On the way home the other day, the SERVICE ENGINE SOON light came on. When I got home I pulled codes and got a PCM P0410 code that decodes to SECONDARY AIR INJECTION SYSTEM fault. Following the link to the troubleshooting section, I found that the most likely cause is a blown fuse in the Air Pump circuit, most likely caused by the pump seizing up from frozen water in the pump, or corrosion from water getting into the pump.

So my question is, what is the computer actually testing to arrive at the conclusion that there is a fault. Does it only sense voltage going to the pump, or does it sense that the pump is not actually running? I hate to just go ahead and replace the pump if there could be some other malfunction. Also, the troubleshooting guide stated that the water in the pump is probably due to leaking check valves in the air circuit, allowing exhaust gas and moisture back into the pump. Therefore, the check valves should be replaced along with the pump. Does anyone have any idea about how big a job this is?

Thanx in advance.

Bob
 
#2 ·
Hey Bob,

Have you checked to see if the fuse is in fact blown?

If so then the pump would be your problem.

As long as the check valves hold vacuum, I wouldn't arbitrarily replace them. The job itself isn't too bad, the hassle comes with chasing down the problem.

Have you done any work to the engine recently? It is easy to knock a vacuum line of when removing the engine cover.
 
#3 ·
Well, I didn't actually pull the fuse. It can't be removed by hand and I'm a little worried about grabbing and pulling with pliers, although another user on this forum has told me that this is a perfectly safe thing to do.

I got another brainstorm, and decided to do a test with a voltmeter. I removed the cover over the fuses and then started the engine. Using the voltmeter, I measured the voltage on both sides of the fuse. I got 12V on both sides. I would expect that if the fuse is blown, that I would have measured 12V on one side and close to zero on the other (open) side. I guess I should take the fuse out anyway and check it with an ohm meter just to be sure.

I also noted that when the ignition was "on" but the engine was not running, that the voltage on both sides of the fuse measured zero, which kind of makes sense. I ran the onboard diagnostics to look for the fault again and the PCM reported the same fault and stated that it was CURRENT. Since the pump does not seem to be powered when the engine is off, how does the PCM determine that there is a fault in the pump circuit. I'm assuming that CURRENT means that the fault was detected as the diagnostics were being run.

Bob
 
#5 ·
I would pull the fuse just to be sure. If you 'finesse' it out rather than 'jerk' it will come out with no problems. The alternative would be to have someone start the car cold while you listen around the driver side wheel and see if you can hear the pump running. It will sound like a whirring noise - think Dremel. It should be relatively easy to rule out the pump as the problem (or not).
 
#6 ·
The computer looks for a sharp change in both upstream O2 sensors indicating excessive oxygen content in the exhaust manifolds when the AIR pump is turned on. So voltages in the pump motor circuit are not checked, though if there's a fault in the circuit the same code will set due to no O2 response when it's turned on. The code is general, and there are many causes. Anything that prevents an upstream O2 from reading below 150mv when the AIR is activated will cause this code. Most often it's a bad pump, to which there are also more than one cause. Make sure the pump works by unplugging the forementioned relay on the P/S firewall and installing a jumper wire from large red to large red, then listen for it humming in the fender, pull an output hose from a check valve and feel for air flowing. If exhaust will flow out a check valve then it's broken and water logging the pump etc. Carbon build up in the passages through the head will cause it.

Here's some previous posts with a lot of good information spread throughout:
http://www.cadillacforums.com/forums/cadillac-deville-1985-2005-including-1985/287873-p-0410-secondary-air-injection-pump.html
http://http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/279795-issues-code-p-0411-2006-dts.html

Vernon
 
#7 ·
Guys,

This morning I got onto my computer and opened the CD copy of the Service Manual that I bought for the car on eBay. I found the section on the Air Injection System and read through it. When I got to the part about how the PCM tests the air pump, it seemed to me that it would not be possible for this test to be done unless the engine was running, so simply activating the DIC and running diagnostic tests would not really show a fault. So I decided to simply clear the code from memory and then start the engine and try again. Lo and behold, no more SERVICE ENGINE SOON light! The engine was cold when I did this, so I took it out and drove it for five miles or so and the light never came on again. I don't know if this was just a "nuisance" fault, or if something is intermittent but I'll just wait and see if anything shows up again.

Thanks for all of the information. I will log it away for the future.

Bob
 
#8 ·
The PCM does detect the fault when the engine is running. it sets the code as current and stores it. the code will remain current, until the problem does not occur for several cold starts, at which point it would go to history. The engine does not have to be running to pull the codes.

It may take several cold starts for the code to set again.

Does the pump run?
 
#10 ·
Moist,

Okay...that's more good information. No, I did not check to see if the pump is running. I decided to try clearing the code first to see if the problem went away, which it did. I was not aware that it might take several cold starts to set it again. I'm not even sure where the pump is located. The drawing of the pump in the service manual does not reflect the way that my car is built, although the manual says that there are two different pumps...one that takes air from the air cleaner, and one that takes air through it's own dedicated filter. Maybe I have the second one. If the light comes on again, I will proceed to take the steps that have been outlined above.

Thanks again for the assistance.

Bob
 
#13 ·
the manual says that there are two different pumps...one that takes air from the air cleaner, and one that takes air through it's own dedicated filter.
:hmm: Huh? Neither sounds accurate.

Sounds like you have a generic repair manual for your car (a cd of the "real" FSM would be pirated anyway), you really need to get yourself a Helm FSM.

Your pump is mounted to the engine cradle, in front of the left front wheel. You'll need to remove the plastic air deflector to see/access it.
:yeah:
 
#11 ·
Sounds like you have a generic repair manual for your car (a cd of the "real" FSM would be pirated anyway), you really need to get yourself a Helm FSM.

Your pump is mounted to the engine cradle, in front of the left front wheel. You'll need to remove the plastic air deflector to see/access it.
 
#12 ·
When I had my P0410 problem, I could reset the codes and that light would go away... sometimes for many drive cycles, but always came back. I wish you the best of luck, but know that it set for a reason to begin with.

For the most part, the fixes are pretty basic once you get the problem(s) ran down.
 
#15 ·
Guys,

My interpretation of the location of the pump, as shown in the manual, may have been incorrect. I believe that the pump was shown without some of the other components in the engine compartment around it, making it appear that the pump was fully exposed. But after some of the comments above, I'll go back and look at it again.

The manual is an official GM service manual. I have no way of knowing if it is pirated. Since it was sold by a reputable seller on eBay, I would hope that it is a legitimate copy.

You are probably right that the light will come on again after the car has been used for a while. I was hoping that this fault was a random occurrence...like the couple of times that the car has locked itself while sitting in the garage all by itself. Or the times that I have exited the car after the seat and steering wheel moved to the EXIT position, and then returned to the car to find that they have moved themselves back to the driving position. (This happens a lot).

Bob
 
#17 ·
Guys,

My interpretation of the location of the pump, as shown in the manual, may have been incorrect. I believe that the pump was shown without some of the other components in the engine compartment around it, making it appear that the pump was fully exposed. But after some of the comments above, I'll go back and look at it again.

The manual is an official GM service manual. I have no way of knowing if it is pirated. Since it was sold by a reputable seller on eBay, I would hope that it is a legitimate copy.
http://www.gmpartsgiant.com/Page_Pr...orIndexID=03&minorIndexID=6K03-036&SortKey=26


http://www.gmpartsgiant.com/Page_Pr...D=6K03-031&SortKey=22&ART_SUFFIX=&SupplGroup=
 
#18 ·
Moist,

MOST of the time, the seat stays in the EXIT position, even after I unlock with the key fob. Once in a while, I come up to the car before unlocking it, and the seat will be in the forward position. The steering wheel may or may not have moved during this time.

Sorry for getting things off track with these comments. I was just trying to explain why I thought that the 0410 code might be a fluke. Maybe I will open another thread about the "mysterious moving seat" some time later.

----------

Ranger,

Thanks for posting these drawings. They make things clearer.

Bob
 
#19 ·
Well, guys....after four days and a number of cold starts, the SERVICE ENGINE SOON light has not come on again. It probably will the next time I start it (LOL). Anyway, if it shows up again, I will be well prepared to attack it, thanks to the information that all of you have provided.

Keeping my fingers crossed...

Bob
 
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