Question about 2004 GMC Envoy
Check engine light comes on. Diagnostic check says secondary air supply failure. Upon removal of air hoses connected to electric air supply pump there is water in hoses and pump. Pump blows good amount of air when engine is first started. After a few seconds the pump slows to a low speed. After emptying water I disconnect negative battery lead to reset code and all is fine for about 50 miles. Then check engine light comes back on. Is it the pump or is it the secondary air valve mounted on engine block? Is it something else?
I have a 2005 Envoy with a 4.2..... Just recently the check engine light illuminated so I read the code after replacing the 20amp fuse labeled cigar. My OBDII connection had no power so if you plug your reader in and nothing check the fuse under the hood labeled "cigar"
After pulling the code P0410 Secondary Air Injection Malfunction I checked the operation of the air pump by removing the hose connected to the solenoid. By the way the solenoid is located on the pass side of the engine top towards the back. After pulling the hose off the solenoid I started the vehicle when it was cold and after 20 seconds or so the pump should turn on and blow air out of the hose. Once I verified the pump was operating I pulled the solenoid then placing jumpers from the Positive & Negative of the battery to the pins on the solenoid. You should be able to hear the solenoid click which says its operating. But mine did nothing so I read across the pins with an Ohm meter and verified the coil was good.
So take some good penetrating oil and fill the inside of the valve with it. You can see the plunger shaft assy in the opening and thats the area you want to fill with a good penetrating oil!!!! Let it sit for a couple of hours keeping it full of oil. The housing is aluminum and the shaft is likely to be a brass material so rust is not possible. Its caused by a buildup of carbon!! The penetrating oil will soften the carbon which in turn will free up the plunger!! MINE WORKS GREAT NOW and plus you will save around $140.00 if you were to buy it from the dealer!!! Or $80.00 aftermarket from RockAuto.com
Posted on Feb 10, 2009
Have the same problem on a 2004 envoy. Was told by my very reliable mechanic that the cause for this is the pump being exposed to the element too much, and it shorts out eventually, a very common problem with this car. Apparently the pump is on the chassis driver side and can easily be removed and replaced, and when removed, a person can hook a 12 volt battery directly to the pump to test if it's working or not before unnecessarily replacing a good part. This part is for emissions only and it's failure does not affect engine performance or milage.
Posted on Jan 03, 2009
Those of u all who have the problem with the secondary air injection system. first check the pump and pump relay by turning key to run position. check to see if the relay next to the air pump is geting a neg and a pos to close it. if its geting a pos and no neg groung the thin drk brn wire and listen for relay to close if pump starts relay and pump are good the drk brn wire leads to the pcm which sends a ground to close the relay the pcm recieves its signal from the engine coolent temp sensor
Posted on Mar 04, 2012
If there was water in it, then the pump is most definatly the problem, there hsould never be water present in the air system. I recommend checking to make sure there is no cracks or dry rot in any of the hoses. If you find one replace the hose.
Posted on Nov 26, 2008
Mr. Sawmarks a have a ? For you . when you relocating the pump that you still have problems?
Posted on Jul 21, 2013
Yes, they fail due to water (condensation) that seizes the fan bearings. I have had to change 2 pumps because of it. There is a kit that is supposed to fix this. I am relocating the pump above the inlet lins so the water runs out. There is a relay and a solonoid that seem to fail just as ofter. I think the relay fails due to the motor seizing and power needs over heating the relay. The solonoid fails due to carbon build-up. This can be cleaned. The entire design is junk and GM should have had a recall on all of these to fix them!!!!!!
Posted on Feb 18, 2013
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