Thank you for the recommendation guys.

The ABS light will turn ON while is in a shop when the car is "driven" while a front tire is on the air or spinning freely.
Such is the case when they perform the emissions test (in California) and when a traction tire is allowed to rotate (up in the air) under engine power.
The ABS unit goes crazy trying to figure out why a wheel is spinning and not all the other ones when the brakes are not applied.
The good thing is that after the car starts driving and the ABS unit performs the self test, and it finds everything to be normal again, then it turns the ABS light OFF.

If the problem persists, then you may have a defective ABS Control Unit.

All the ABS control units (Installed on 96 and newer 850 and 70 series) will eventually fail after they reach 65,000 miles or 5 years. The average is 85,000 miles and/or 6 years for failures.
The erratic ABS light and/or no trouble codes is an indication of a defective ABS unit.
A dealer will charge about $120.00 to diagnose the problem and tell you that you need a new ABS control unit.
Having said that. Here is an alternative to correcting the problem for good.
Vitor's web page
Click on the ABS / TRACS Repair link.