The Colorado Auto Dealers Association has parted ways with longtime CEO Tim Jackson.

No reason for the departure was given. In a Friday release, the board said it had appointed Matthew Groves, its vice president of legal, regulatory and compliance, as interim CEO, effective immediately.

Jackson has been CEO of CADA since 2004 and has been a high-profile voice for dealers in the state and nationally. Earlier this year, he and CADA championed a legislative effort to force automakers to reimburse dealers for warranty work at the higher rates dealers charge retail customers.

The separation appeared to be sudden.

As late as Thursday, Jackson, who is prolific on Twitter, posted that he was at the Colorado State Capitol, and he posted on automotive topics.

Jackson was not immediately available to comment. An attorney for CADA referred Automotive News to Jackson, while a member of the CADA board declined to discuss the issue.