An ABS/cruise control fault indicator on my dash panel, but no check engine light. Figured the fault would require a dealer visit to diagnose. My dealer is 50 miles from home, and any visit is a major event. So... after some research figured the usual problem might be dirty wheel sensors, which is something even I can "clean". At 32K miles on my '07 the wheel sensors were still quite clean with no visible contamination.
After cleaning ABS fault indicator was still illuminated, but now check engine light iluminated. Using my trusty ScanGauge revealed a "34" (sic) code indicating a faulty right front wheel sensor. Purchased a oem wheel sensor and installed it. Not a big job requiring only common sense, BUT there is a teeny, tiny, little mounting tab on the sensor which must mate up with a gap on the wheel. It is easy to overlook.
My point is that the check engine light monitors not only emission components, but also ABS system.

 

Very interesting...but I don't see how or why the CEL would monitor the ABS...so I am just going to offer another possibility: low battery voltage. If your battery is not putting out full voltage (old battery, infrequent use, short trips...) then you WILL get random warning lights (yes), badly functioning or non-functioning seat, window, electric top modules, frozen touch screen, erratic flasher operation...it can be any of these or a combination of these and others. So if your car exhibits any further odd behaviour, I would definitely go to the battery as culprit first. This is a well-proven phenomenon with these cars.

 

No problem with my battery - my running voltage is consistently at about 14vt. Nevertheless, good comment on battery. Something to check initially.
There is no doubt that CEL also monitors ABS simply because the "34" code says "faulty right front wheel sensor."