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Mazda Ed
Mazda Ed, Auto Service Technician
Category: Chevy
Satisfied Customers: 2223
Experience:  ASE Master Technician, Mazda Master Technician, GM and Ford factory trained. 15 years experience.
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1997 Chevy: service engine light on (bad o2 sensors..emissions..MIL

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I have a 1997 Chevy Silverado with a 305 engine. Had the service engine light on (bad o2 sensors) replaced them. Went in to get it smogged passed emissions but failed the MIL test. OBD2 would not connect between the truck and smog comp. Checked fuses, o2 fittings, just about every thing I could think of, even went as far as taking to other smog shops to hook up to their dyna machines (4 in all) and (3 hand scanners) all came back the same Communication Error. Don''t think it would be a bad computer cause it starts up with no issues. No Service Engine Light is coming on. I am about to lose my mind. Can anyone please point me into some type of right direction
Submitted: 8 years ago via
Category: Chevy
Expert:  Mazda Ed replied 8 years ago.


I can tell you that after several attempts to communicate many states allow for a waiver of that portion of the test. You must have been able to commnicate with the computer at some point to get the O2 sensor codes?

You will want to check all of your power, grounds and the CLASS 2 data line for opens or shorts.

Object Number: 52617  Size: FS


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