After retiring as a player in 1997, Maran started his coaching career in 1997 at his former side Chievo as a coach, he joined Brescia as a youth coach in 1998 and stayed there for 2 years before becoming the youth coach at Cittadella in 2000.
Maran was appointed as the head coach of Cittadella in 2002, before returning to Brescia this time as Head Coach in 2005, however he was replaced by Zdenek Zeman as Head Coach in 2006. He joined Serie B giants Bari in 2006, however was sacked after a string of poor result and replaced by Giuseppe Materazzi in February 2007.
He joined Triestina in June 2007 and managed the club until 15 June 2009. The following day he joined fellow Serie B side Vicenza and managed to help them avoid relegation. On 15 June 2010, his contract at Vicenza was extended for a further 2 years. However he was sacked a year later as Vicenza Head Coach on 6 June 2011.
In 11 June 2012, following a mixed career in the lower leagues, he joined Catania in Serie A. After taking over he led Catania to a record-breaking season where they accrued 56 points from 38 Serie A matches. The season also saw Catania take a record amount of home wins in one season, its record number of victories overall in a single top flight campaign, as well as its record points total in Serie A for the fifth consecutive season. Catania finished 8th in Serie A, finishing behind Lazio in 7th place.
Maran, however, failed to repeat his impressive results in the 2013/14 season, and was ultimately dismissed on 20 October 2013 after a 1–2 loss to Cagliari Calcio that left Catania in the relegation zone. He was replaced by Luigi De Canio.
On 15 January 2014 he was hired again as the Catania head coach, before being sacked for the second time later on 6 April, after five defeats in a row and with the team bottom of the league.