Plymouth did little to advance their play-off chances and Barnsley nothing to help their fight against relegation with this draw.
A point was the most either side deserved, with Barnsley's Bruce Dyer's 13th strike of the season in the 65th minute equalising Plymouth centre-back Graham Coughlan's 14th minute opener.
Both teams swapped unconvincing half chances before the Tykes fell victim to a training ground goal, made by one central defender and converted by the other.
Paul Wotton slung over a corner to the far post, were Coughlan timed his run perfectly to arrive ahead of Dyer and thump home.
Dyer almost made amends for his lacklustre marking, forcing Romain Larrieu into a save and the Pilgrims goalkeeper then made an excellent triple stop.
First, the tall Frenchman flung himself to his right to tip away Mike Sheron's curling shot and he was quick enough to get up and touch Gary Jones' shot from the rebound on to the post. Just for good measure, he then punched away Robbie Williams' dangerous cross.
Plymouth also hit the woodwork before the interval, when David Norris slammed Micky Evans' headed knockdown from David Worrell's cross on to the bar.
They were again unfortunate not to extend the lead before the break when Ian Stonebridge spun away from Anthony Kay and unleashed a shot which keeper Andy Marriott did well to parry.
Marriott, though, continued to be troubled by Plymouth's corners early in the second period and Paul Bernard came within a whisker of repeating Coughlan's earlier far-post goal, with Brian McGlinchey this time the provider.
Barnsley made Plymouth pay for that miss when sub Kevin Betsy on for Kevin Donovan, linked with Sheron to set up Dyer for him to curl a shot past Larrieu from 12 yards.
With ten minutes to go, Dyer was excellently played through by Neil Austin, but with just Larrieu to beat, he toe-poked the ball to goal and the Pilgrims keeper stuck out a foot to stop the ball.
Plymouth sub Martin Phillips nearly made a name for himself three minutes from time, following up Norris' break on the right, but Marriott superbly denied him.