98 GMC 1500 Pickup codes P0410 and P1404

CraigE

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#1
I have these codes set on my V8 1998 Pickup. Any hints? I swapped in a known good EGR valve and will wait a while to see if the codes clear. I do not have a scanner handy to clear codes. The other code P0410 for secondary air injection system fault is a puzzler to me. What is the secondary air injection? This truck does not have an air pump. Thanks CRAIG
 

Gus

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#2
Secondary air injection, blows air into the exhaust, to help unburned fuel from a cold engine, to burn up before it reaches the cat.....

It's usually an electric pump, so it won't be like old air pumps that are belt driven....
 

CraigE

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#3
Any hints on diagnosing the code setting problem? Where is this electric air pump? Thanks CRAIG
 

Transman

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#4
The air pump is a chronic problem on these, they mount it under the battery and the intake pulls water every time you hit a puddle. There is a TSB on a revised pump assy. This one will have a hose that you route along the side of the battery and up in the air a bit. Also don't be surprised if the map sensor is going bad (if it has one). The only function of the MAP is to verify the egr is working on this vehicle. Post back, Transman
 

CraigE

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#5
After I installed the other EGR valve the codes all cleared up after about 35 miles of driving. Thanks for the info on the air pump, I never knew these had one. CRAIG