i have a 2001 silverado v8, because i got a new battery ive had to drive my truck (spare vehicle) so a sensor will flash for a smog. well ive driven it a couple hundred miles and still one of the sensors wont "flash". ive tried drive cycles where i cold start the truck for a few mins, then drive on the freeway for so many mins, coast til down to 20mph, then back up etc...ive tried a few of those and no luck. anyone else have a similar issue?

thank you

 

bump!

 

to pass a emission test all the component monitors must run and pass. what monitor are you trying to complete? you will need a scan tool to find out. Once we know which monitor is incomplete, we can determine what is stopping it from running.

 

Had the opposite with my Camaro. had to drive it over 200 miles so that the evap system would allow for a proper smog test.

 

evap won't run if the fuel level is over 85% or lower than 15%. Some won't run if the ambient temp is to low; so they allow conditional passes on evap in winter.

 

the tech said the secondary air is the one we need to flash and the he can help me fix the heated o2. he said at that point we wont have to worry about the evap....any suggestions to get that secondary air to flash or how to fix it? below is a pic, thanks!

 

flashing refers to reprogramming a module; not related to what you are doing. you need to get a monitor to run and complete.

the secondary air monitor will not complete until the heated 02 sensor monitor runs and passes. it needs data from a working 02 to do it test. the monitor will be inhibited until the o2 pass. fix the o2 and the air monitor will run

 

thanks! I’ll look into those sensors. Odd because The check engine light isn’t flashing. I’ll take it to auto zone And borrow their obdII to check for any codes flashing. Maybe I can just clean the sensors and see it’ll get it to work.