General Motors Corp. and Chrysler LLC have reopened merger talks, as Chrysler owner Cerberus Capital Management LP has signaled its willingness to give away part of its ownership in the auto maker, say people familiar with the discussions.

With cash running low at both companies, Cerberus took the initiative to restart discussions that sputtered just weeks ago. At that time, both GM and Chrysler viewed a business combination as impractical and as a distraction from their mounting liquidity problems.

The...