hey guys,

i got my registration renewal notice about 5 days ago on my SUV (i live in cali). It also says that i need to get my smog done.

I have my service engine light on and I took it to a family mechanic and he was able to turn it off for me. he also said that i should drive about 60-80 miles before i take it in for a smog check. I asked him why and he said because if i take it in too early, the smog check computer will detect that my internal computer has been 'cleared'.

is he blowing smoke or is this true?

 

It's true. The ECU's in vehicles will keep a short term memory of the codes thrown previously. I'm not sure of how long it retains the memory, 60-80 miles sounds about right.

 

is it purely mileage based? wow.. new news to me

 

I am not sure about the milage based part, maybe someone can chime in on that. But yes ECU's do retain in memory codes thrown recently.

 

ok thanks..ill wait about 60 miles..

i hope it doesnt turn back on within 60..

or i hope i dont go to the smog check place and they reject me because of the memory codes it retained...

 

Did your friend mechanic tell you what the code was? Chances are its something you might need to get fixed anyways all together.

 

yeah it was an O/2 sensor high or something... he said that i dont need to replace it..

 

If it is the 02 senor the light will return shortly but hopefully not before you get your smog test.

 

if it comes back on before 60 miles, then i should replace it, correct?

 

update.

i drove 60 miles and i got my car smogged successfully without the light coming back on.

fyi --- smog check stations will not pass ur car if u have the light on. some shady stations will smog even with the light on.. then take ur money and say ur car wont pass bc the light on.

 

You should replace the O2 sensor and yes the check engine soon will come back on sometimes within a week and others before you're out the driveway.
Gary

 

most smog stations will give you a free re-test. look out for those!