hi there. first time poster, firstly i'd like to apologize if this is not the correct section in which i should be posting this issue. i figured it's more of an exhaust system question than an engine question or anything else but i could be mistaken.

i have a 2001 blazer (2-door vortek v6) which i am attempting to make ready to pass califonia emissions.

i'm not throwing any codes, but i can't get my SECONDARY AIR obd monitor to "ready" despite a few successful drive cycles and several cold starts. i have also reset all monitors a few times just to make sure they are going "ready" consistently. is it possible that this issue is the result of a blown fuse, or would it invariably throw the P0410 if the fuse was blown? this is the only monitor that won't reset.

i should mention that, at first, it was this and the catalyst monitor that were hanging, but a bottle of cat cleaner and a few drive cycles has done the trick for the cat.

i'd love to hear your feedback on this. thank you for your time.

update: i took an ohmmeter to the fuses dedicated to the secondary air system, and neither the 30amp nor the 10amp fuse were blown. still not throwing any codes, and the SECONDARY AIR monitor still will not go "ready". i am perplexed. any ideas?

 

Do yourself a favor, look up fail test parameters on the internet for your state. Some states will pass you with one "not ready"


If that is the case print it out and bring it with you.






For crapp sake if that's the only thing going on do not disconnect the battery for any reason!

 

The only reason a monitor will not run and complete, is when the drive cycle has not been done correctly. The PCM constantly "watches" for a certain drive pattern, if the pattern is duplicated by the driver, the monitor will run and complete. Each monitor has its own specific drive pattern that must be duplicated, perfectly. Follow this General Motors Driving Cycle exactly as written. Each step must be completed. You do not need to do the steps in order, but each step must be done exactly as written. When finished, check all monitors, if you did it correctly, all monitors will be complete. With some careful planning and practice, it takes about 15 minutes.

EVAP and catalyst monitors are the most difficult to run and complete. It's not uncommon for them to go days, weeks, or even months before they run and complete during normal driving conditions.

 

though the california government website regarding emissions does not state this explicitly, according to the technician at the smog station i visited (i am in california), all monitors are required to be ready and there must be zero codes before i can even pull onto the dyno.

 

i found the guide you recommended when i first started this process and i have followed this exact guide to the letter no fewer than ten times. my EVAP and CATALYST monitors are ready with no problems, it is only the SECONDARY AIR monitor that will not go to "ready". i have an obd II reader, which i have been using to pull my results after every drive cycle and after each of the several cold starts i have performed, also to the letter of the guide you linked to.

 

The link is copyrighted material from GM. I can scan the drive cycle from the GM "dealer issue" shop manual if you'd like, but there's no point, it says the same thing. If you have access to a TechII scan tool, you can force the monitor to run and complete, that's the only other option.

 

the guide that i found and followed was located here, and it says the same thing:
OBD II Drive Cycle (reset car diagnostic monitors )

i have gleaned from multiple sources that the SECONDARY AIR test is done in the first step of the drive cycle, and that if all the other monitors are ready, i do not need to perform any steps past the cold start at this time.

a few things that might be worth mentioning:

1) my air conditioning coolant system was diagnosed as having multiple leaks when i first bought the vehicle. i have no real use for the ac since i live in california, so i've never bothered to have it repaired. that being said, i'm not so sure the compressor works, which i figure may be relevant since the first step of the drive cycle procedure requires that i have my ac on during the cold start, contributing to the electrical load (though the guide does not specify whether the electrical load is required on that and the rear defrost circuits alone to "ready" the monitor, or whether i could apply additional load via the headlights, dome light, stereo, lighter outlets etc.)

2) i've listened closely during the cold start, and at no time do i hear any indication of a change in state upon completion of the two and a half minutes required. i know that the secondary air pump exists for the purpose of injecting air into the exhaust system to preheat the catalytic convertor, and i would think that i should be able to hear this pump turning on/off. am i incorrect in this assumption?

3) i have read about how there is a known issue with the secondary air component's air injection inlet valve on these vehicles, wherein it tends to collect condensation and corrode open. my understanding is that this can overload the secondary air system resulting in a monitor failure if not a blown fuse. should this be the case, i would have to remove the unit to inspect it which i am trying to avoid if the issue can be resolved otherwise.

the last option i will try if there are no other suggestions will be to approach one of the mechanics at the chevy dealership by my work to see if they'd be willing/able to force that one monitor for me.

thank you for your help, i appreciate it.

 

 

On my 2001 4WD Blazer I'm getting an occasional P0410 (only 3x in last 2 months) and also noticing that the Secondary Air testing is not completing (the only readiness monitor not completed). We have no emissions testing here in Indiana, but I don't like to ignore things. FYI I have HP Tuners Software which has bi-directional control and allows select devices to be turned on/off and otherwise controlled through the laptop. I am able to toggle the AIR solenoid and turn the AIR pump on/off. With the engine off I can hear a relay click when the solenoid is turned on/off and I can hear another relay click when I turn the pump on/off - but cannot hear the pump running at all. Tomorrow will verify 12V to the pump and that ground is good. If so, will go to the pick and pull junkyard on Sunday for the part, which seems to be a 2001-only part according to Rock Auto. Wish me luck! I hear it is common for these pumps to get moisture in them and seize up.

Factory diagnostic chart indicates that O2 sensor should approach zero IIRC. Tell you exactly how to do the test, but IIRC you have to be able to definitively turn on the pump (not just rely on timing). Specifically says that 100mv is not good enough and may happen even with system inop. Is that the spec/info that you are searching for? If so let me know and I will copy it for you.