no codes read by scanner

CHEVROLET CAVALIER
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TERYLGAR
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I have a 2000 CNG Cavalier, 80,000 miles, 2.2L. The check engine light is on. I took it to two mechanics. Their scanners (one was a snap-on, I don't know about the other) indicated no codes, although the light was on even as the scanner was connected. A call to snap-on was unproductive. Does Chevrolet have a special scanner to scan codes? Does a CNG vehicle have aditional codes?
Nov 4, 2007 at 3:03 AM
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2CARPRO JACK
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They have a scan tool (Tech2) but any scanner should be able to read the codes.We are talking about the Check Engien Light and not a maintenance reminder light correct? I m not trying to insult your intelligence, but usually the scanners will say "no communication" , but if the light is on, there should be a code in it.There is no way to read them without a scan tool.
Nov 13, 2008 at 9:15 AM
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MMPRINCE4000
  • ✓Experienced Mechanic
  • 8,548 POSTS
Too add to what Jack said:

If there is no communication, you will get the "no communication" indicator.

If there are codes (active, pending, history) the scanner should display them regardless of fuel used.
To verify this, put the scanner in live data mode, if it displays live data, then the scanner os OK.
There are 4 types of codes, "P" (powertrain), "C" (chassis), "B" (body) and "U" (Commnication codes). The snap-on should read all 4.

If no codes are displayed, then you have a problem with the SES light circuit.
Nov 13, 2008 at 10:33 PM
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