2002 GMC Envoy Service Engine Soon

2002 GMC ENVOY
90,000 MILES • 6 CYL • 4WD • AUTOMATIC
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KHLAIFAT
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One month ago I had the "Service Engine Soon" light coming out in my 2002 GMC Envoy. I had driven the car to the repair shop. The diagnose was "EVAP system error", they conficed me that such type of problems is caused by oxygen sensor. After changing the ogygen sensor, the light is still on and even stronger (lighter). I was provided by too many guesses for the cause of the problem. Can you help me guys to find out why the "service engine soon" is still on?
Thanks in advance
Jan 3, 2009 at 11:42 AM
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BRIAN 1
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what was the code? an 02 sensor will not cause an evap code,how did the repair shop diagnose it? were they guessing?need to monitor evap data with a scan tool or put a evap smoke machine on it.(it fills the the sys with nitrogen and smoke to find a leak). post back with the code and will advise from there.
Jan 3, 2009 at 1:32 PM
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KHLAIFAT
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The code is P0440 (evap system error).
Feb 2, 2009 at 5:36 AM
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BRIAN 1
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have the evap sys tested with a smoke/nitrogen machine to find the source of the leak.
Feb 2, 2009 at 10:27 AM