This winter and last, the ETS light in my '99 V70 5-speed comes on when I start the car in ambient temperatures of about -15C or below. The car seems normally drivable around town, and the ETS light will not come on if the car is restarted after the engine is warm (say 20 min driving) or after its been parked indoors for the day.
But also, once, in the middle of a highway drive at about -5C, the ETS light came on when I was accelerating in high gear at about 120 km/m (70 mph) and there was a noticeable degradation of performance, though the car remained drivable. I completed the trip at highway speeds but without passing anything. At the end of the trip the car idled roughly, but after 20 mins rest it started fine with no ETS light.
In all cases the ETS light stays on until I shut the engine off. I'm guessing that whatever logic controls it only activates at engine start.
I'm inclined to more or less ignore it; is it something that really should be checked? Given Toronto's weather and my frequency of driving, the first phenomenon only happens a half-dozen times a year, and the latter has only happened once.
Chip C Toronto