You can fail this part by losing the van from your sight. This is where you use your Disruptor on the weapons van and follow it to the secret hideout. Check the side mission tab to get new intel from Nightwing about the whereabouts of weapon vans. You have to progress with the story and bring the Batmobile to Founders’ Island.
With the help of a new gadget (the disruptor), Batman marks weapon vans and follow them to cache hideouts.Batman teams up with Nightwing to defeat Penguin (Cobblepot) and destroy his weapon caches.