Expert: Van - 9/12/2005

Question
Van,
I've got a 99 Monte Carlo 3.1 w/ approx: 70k on it.  Rarely have had any problems and keep it maintained.  For the last 3 months, the ABS light will come on one day will driving, then go off for several days and so on!  I have had the brakes checked, as well as the abs master and have been told nothings wrong(of course the abs light is off when I take it to be checked.  Any ideas?  Also, occasionally the the check engine light comes on then goes off.  Then it will stay on.  I had the trouble code read, and it shows a air evap malfunction.  What is this, and can I fix it?  When the code is reset it will stay off for about a week.  Thanks for any suggestions you may have.

Answer
Hello David,
The air evap problem could be something as simple as a loose gas cap. A gascap with a bad seal, a crack in a vacuum heose, especially one related to the vapor canister.

The ABS could be moisture in a wheel sensor wire harness connection, some metal particles collected on a sensor, or the high stop light bulbs blown, although that should turn on the cruise light also, but still a possibility.
And make sure your parking brake lever is released all the way.

Low brake fluid, or some air in the system could also cause the ABS light.

Van