How to Complete the “Fault Hunting” Side Mission in Borderlands 4

The “Fault Hunting” side mission in Borderlands 4 is a multi-part quest that takes you deep into the underbelly of a hidden facility, forcing you to solve two complex puzzles before a climactic boss fight. This guide will walk you through every step, from picking up the mission to taking down the final boss, Genone. It’s a lengthy and rewarding quest, so be prepared for a challenge.

The mission begins in the Ruined Sumplands region of Carcadia Burn. You can pick it up from an NPC named Leopold at the Society for Amateur Seismology Enthusiasts. He’ll task you with investigating a series of unsettling tremors that have been plaguing the area. Your first objective is to head to a nearby cave to find the source of these tremors.

Part 1: The Rumbling Cleft and the First Puzzle

• Find the Cave: Follow your waypoint to a large cave entrance. Inside, you’ll need to navigate a series of platforms and use geysers of air to reach higher ledges.
• Defeat the Creeps: Upon entering a large cavern, you’ll be ambushed by a group of Creep enemies. Take them out to progress.
• Find the ECHO Log: After defeating the enemies, look for a glowing green ECHO Log labeled “Seismic Damage” near a destroyed drill. Picking it up is an optional but recommended step. Examine the large bulkhead door nearby, and Leopold will note that it’s an Order build, not listed on any maps.
• Enter the Facility: Look for a newly opened air vent on the ground and use it to reach a high ledge. Crawl through the narrow passage and follow the hallway until you reach a malfunctioning door. To open it, you must shoot a green door release canister on the other side. Time it carefully for when the door partially opens.
• Solve the Power Rerouting Puzzle: Once inside the server room, you’ll be tasked with restoring power to the central server console. Go to the large generator with three cylindrical tubes across the room. You must use your Grapple ability on the junction levers on the ceiling to redirect the power. The goal is to create a direct, unbroken line from the generator to the server console. You can rotate the pieces to make the connection.
• Hack the Server: Once the power is rerouted, return to the server console and initiate the hack with ECHO-4. Be ready for another wave of Creeps to spawn and attack. Take them out before the hack is complete.

Part 2: The Search for Genone

With the server hacked, you’ll learn that the tremors are the work of an AI named Genone. Your next objective is to hunt him down. Genone’s actual location is in a different region entirely, in the Yawning Yard, which is part of the Carcadia Burn region. The best way to get there is to fast-travel to a nearby safehouse, such as the Makeshift Chalet, if you have it unlocked.

• Locate the Second Lab: Once you reach the Yawning Yard, you’ll need to use your Echo Location ability to find a hidden cliffside entrance. Drop down a couple of ledges and enter the cave.
• Solve the Second Puzzle: Inside, you’ll be met with another locked door and a second, more complex power rerouting puzzle. This one is similar to the first, but with more components and a different layout. Your goal is to direct power from the generator to the console by the locked door. The puzzle requires you to turn various junctions to create a clean circuit.
• Confront Genone: Once the door is unlocked, you will enter a room that traps you. Genone will invite you to a final showdown. Proceed to the boss arena when you are ready.

Part 3: The Boss Fight and Mission Completion

Genone is a tough boss, and this fight can be a challenge. He is a beefy synth with two health bars, one with a shield and one with armor. This means you need to come prepared with the right elemental weapons.

• Boss Fight Strategy:
  • Shields: Genone’s first health bar is protected by a shield. Use a Shock weapon to quickly deplete it.
  • Armor: Once the shield is gone, his second health bar is made of armor. A Corrosive or Cryo weapon is the most effective against this.
  • Healing: Genone has the ability to heal, so focus fire and use your most powerful weapons to minimize the time he can recover. He will often heal after his shield has been depleted, so this is a crucial moment to deal a lot of damage.
  • Enemy Support: Be mindful of the other synth enemies that will spawn throughout the fight. While focusing on the boss, be sure to take them out to avoid getting overwhelmed.
• Shutting Down the Facility: After you defeat Genone, Leopold will ask you to shut down the facility for good. Grab the keycard labeled “Zadra’s Control Room Keycard” from the console behind where Genone was located. Use it on the console up the stairs to shut down the facility and complete the mission.

Completing “Fault Hunting” will earn you a significant amount of XP, cash, and a new assault rifle weapon skin. It’s a fun and challenging side quest that is well worth the effort for any Vault Hunter.

Happy hunting!