Typically, in an anxious game, both goals came as the result of uncertain defending.
Cardiff opened the scoring midway through the first half after Argyle goalkeeper Luke McCormick failed to deal with a corner from new Bluebirds signing Neal Ardley.
His weak punch fell to Richard Langley on the edge of the box and the Cardiff midfielder's shot bounced up off the turf and squeezed past Argyle captain Paul Wotton on the line and in off the post.
The visitors could nearly doubled their lead in first-half injury-time when rookie striker Cameron Jerome broke free of the Argyle defence, but his shot across McCormick went wide of the far post.
Argyle won five corners in the opening ten minutes of the second half, but were repelled by Cardiff, whose resistance was finally ended by Hasney Aljofree.
The Argyle centre-back was in the right place at the right time after Cardiff failed to clear Wotton's flag-kick, smashing home the ball after latching on to Mickey Evans' nod down.
Cardiff abandoned their negative approach, and the game opened up as Argyle introduced Dexter Blackstock, and switched to 4-3-3.
For their part, Cardiff tried to snatch the points on the counter-attack by replacing both strikers with substitutes Alan Lee and Michael Boulding, on loan from Barnsley.
The draw benefited neither team, who still need a win or two to ensure they will remain in the Championship next season.
Cardiff's point also came at some cost. Welsh international defender Rhys Weston left the ground on crutches after being stretchered from the field with a painful ankle injury.