im getting a secondary air injection system malfunction when i read the code, what could be at fault? when they had the recall for the 96z28, they changed the egr valve and the air pump maybe 2 years ago, i did search and found that it could be the fuse or the airpump, ill check the fuse but if the fuse is ok and the pump is fried since it was done under a recall do they replace it again? thanks for the help

 

ok i checked the relay and its at 81 ohms, but i switched the relays around just to make sure, i put the ac/ compressor relay in the airpump's slot, both relays are they same thing, now i couldnt find a airpump fuse in the engine compartment or inside the fuse cluster , on a side note, if the airpump was bad when i turn on the ign i can hear the airpump turning on, if the airpump was dead would it even turn on?

 

I had the same problem with my 96 Z28. The fuse was blown. The fuse is located under the hood, there is a diagram inside the fusebox cover. Look for fuse 7 (A/P FAN).

In my case I thought the problem was the air pump motor since it had a very small DC resistance (like .3 ohms small) which would require about 40 amps initially, and the fuse was only rated for 20 amps. But after I replaced the motor the fuse blew again about a week later. I checked the resistance again and it was very low again. Not sure if it was that way when I brought it as I never checked it. This time I switched the A/P relay with one of the 3 fan relays and so far the fuse has not blown again. But I really don't think there is anything wrong with the relay as it ohmed out at about 80 ohms which is what the fan relays measure also.

By the way, the A/P circuit is shared with the engine fan relay circuit, so if you blow fuse 7 then your fans will not work either. Be careful you don't overheat your engine.

 

i checked the fuse it requires a 20 amp fuse and there was a 30 amp one in its place, its not blown but would that be the cause of the problem im having with the fuse being a 30 instead of a 20? i wouldnt think so but im not sure, and like i said earlier the airpump is working becasue i can hear it when i start the car, thats why im stumped why its throwing the code

 

No, a 30 amp fuse in place of a 20 amp fuse would not be the root cause of the problem. But I am curious as to how that 30 amp fuse got there. I wonder if that was part of the A/P emissions recall work that was done?

If the A/P is working then, there is also a secondary air injection bleed solenoid valve that is part of the A/P circuit. When I measured mine it was about 33 ohms which is about right for a solenoid. The solenoid is wired from the A/P so follow the wire from the A/P to locate the solenoid.

 

ill do that, since i have you i have another question, does the airpump only come on when the engine is cold? once the engine is warmed up the airpump shouldnt come on right? when i threw the code the engine was hot and i had it at WOT, thats when the 0410 code appeared, so why would i get that code in the first place if the airpump is not even turned on?

 

I just did a search on this forum and found some info that Injuneer posted a while back, "According to my code listing, the P0410 sets when the PCM does not see the correct response to the air flow from the AIR pump. The "active" part of the diagnostic turns on the AIR pump during closed loop operation, and looks for a lean condition at the O2 sensor (less than 222mV for more than 1.5 seconds). You can't disconnect the AIR pump in OBD-II without getting the codes. It has to be "programmed out" of the PCM."

Based on this info, and if your solenoid checks out, then the problem is most likely the O2 sensors are no longer operating in their full range, and during the A/P diagnostic cycle they may be giving false information to the computer. You would need a scan tool to monitor the O2 sensors. A good sensor should be constantly switching from 100mV to 900mV during idle in closed loop.

 

i do have a scan tool and ill check the 02 readings tomm, you have been very helpful thanks, BTW how many 02's are there on the z28? 4 or 2

 

My understanding is the same as yours, the pump only comes on when you first start the engine to help get the O2 sensors into their operating range quicker. And apparently it will also come on to run the self diagnostic. Perhaps yours kicked on to run the diagnostic the same time you happened to be at WOT. In which case I would just delete the code and wait to see if it ever comes back. Your not doing any harm to the engine.

 

There a 4 sensors. 1 on the left and right before each cat and 1 after each cat. I believe the ones before the cats are the ones you need to be the most concerned about. The other 2 are there just to make sure the cats are working.