The Sentinel Control System Companion in Fallout 4 turns a regular power armor frame into a walking, talking combat robot that does not take up a follower slot. Unlocking it is tied to a Creation Club side quest called “Malevolent Malfunction,” which plays out early in the Commonwealth and ends with your own AI-driven suit of armor.
What the Sentinel Control System actually is
The Sentinel Control System is a pre‑War experiment created by West Tek and General Atomics International. Instead of putting soldiers inside power armor, it embeds an AI directly into the frame. After the Great War, the Brotherhood of Steel recovers a handful of these “sentinels” and brings several units to the Commonwealth in 2287.
In gameplay terms, the sentinel you unlock is:
- A power armor frame that moves and fights on its own.
- Fully compatible with any power armor pieces you own, including Creation Club and modded sets on supported platforms.
- Configured as a robot-type companion that does not use the standard follower slot, so you can bring it along in addition to a normal companion.
- Immune to power armor durability loss while it is wearing the armor.
Once activated, the frame can be set to standby (off) or escort (follow) mode, and its personality can be switched between several familiar robot voice packs.
How to start the Malevolent Malfunction quest
After installing the Sentinel Control System Companion Creation, a new side quest named Malevolent Malfunction becomes available. The game does not mark a map location at first. Instead, it kicks off with a distress transmission.
| Step | What to do | What you see in game |
|---|---|---|
| 1 | Load any save in the Commonwealth. | A radio station called “Radio Distress Signal” appears in your Pip‑Boy. |
| 2 | Tune in to the distress signal. | You hear beeps and, once in range, a percentage readout for signal strength. |
| 3 | Roam near early‑game central locations. | The signal originates near Drumlin Diner, just south of Concord, at a Brotherhood battle site. |
The signal behaves like other radio tracking quests in Fallout 4. If you only hear static with no percentage, you’re still out of range. Move between nearby map markers or fast travel around the central Commonwealth until a “XX%” strength value appears, then walk in the direction that makes that number climb.
Finding the rogue sentinels near Drumlin Diner
Following the distress signal leads to a skirmish site on a road intersection near Drumlin Diner, south of Concord and west of Lexington. Here, you’re ambushed by two hostile Sentinel power armor units painted in Brotherhood Outcast colors and equipped with T‑45d pieces.
The quest stages progress like this:
| Stage | Objective | Notes |
|---|---|---|
| 20 / 30 | “Defeat the Rogue Sentinel Power Armor (1/2)” and “(2/2)” | Kill both AI‑controlled suits to stop the attack. |
| 35 | “Investigate the battle site” | Search the area after the fight. |
| 40 | “Read the Sentinel System Log” | Loot and play the log to unlock the next location. |
When combat ends, inspect the road and wrecked vehicles. You’ll find two dead Brotherhood Outcasts, Knight Maria Harper and Scribe Gael Vasquez, both carrying holotapes. One of the key items is the Sentinel System Log, which explains that a Brotherhood scribe named Dawson Wakefield sabotaged the mission and fled to a nearby propane facility.
Reaching the propane station and dealing with Dawson
The system log points you to an unmarked propane station south of the Federal Ration Stockpile. On the map, look directly south of that named location for a small, industrial cluster of tanks and a building: this is where the rest of the quest plays out.
When you arrive, you get a new objective to confront Dawson:
| Stage | Objective | Details |
|---|---|---|
| 50 | “Go to the propane station” | Travel to the unnamed Schoelt propane station south of Federal Ration Stockpile. |
| 60 | “Kill Dawson” | Dawson opens fire as soon as you get close; there is no peaceful dialogue path. |
Dawson Wakefield is flagged as a legendary enemy. He carries an automatic laser weapon with a legendary effect, so expect a tougher fight than most early‑game encounters, especially on higher difficulties or with a low‑level character.
Once Dawson is dead, the quest shifts to tracking down his intel:
- Loot his body for a key to his nearby footlocker.
- Use the key to open the locker inside the building at the station.
- Collect Dawson’s Holotape and the Sentinel Program Mission Report.
Playing Dawson’s holotape advances the quest and fills in the story. He reprogrammed the sentinels to attack his own patrol so he could continue feeding information to the Institute. The holotape also contains the passcode you need to control his remaining Sentinel unit.
Picking up the bonus paint jobs on the way
The propane station hides more than just plot devices. Inside the same building where you find Dawson’s holotape, there’s a new issue of the Hot Rodder magazine series. This issue unlocks a “Racing Stripes” paint job for both power armor and the Pip‑Boy, giving you a bright blue scheme with a stripe motif.
Later, when you finally activate the Sentinel itself, you also unlock the Brotherhood Outcast power armor paint job, matching the red‑and‑black armor you saw on the rogue units. Between the two, the quest guarantees multiple full sets of T‑45d pieces with the Outcast paint, plus the additional cosmetic options for your own suits.
Activating the Sentinel power armor companion
At the propane station, Dawson’s Sentinel power armor is wired into a power armor station, powered down. Interacting with it before you find the passcode fails with a prompt telling you a password is required. After listening to Dawson’s holotape, the quest sends you back to the frame with a new objective.
| Stage | Objective | Outcome |
|---|---|---|
| 61 | “Read Dawson’s holotape” | Unlocks the passcode and background on his betrayal. |
| 65 | “Find the passcode to the Sentinel Power Armor” | Completed when you realize the code is recorded on the holotape. |
| 70 | “Activate the Sentinel Power Armor” | Use the passcode to hack and bring the frame online. |
When you choose to activate the armor, a short sequence plays as your Pip‑Boy interfaces with the Sentinel Control System. The quest completes with a log entry describing that you’ve taken control of Dawson’s Sentinel unit and that it is now ready to defend you with a laser rifle.
At this moment, you also unlock the Brotherhood Outcast paint for your own use at power armor stations across the Commonwealth.
How the Sentinel companion behaves
Once activated, the Sentinel becomes a persistent companion that follows you in its own frame. It defaults to T‑45d armor with the Outcast paint and a standard laser rifle, but you can customize it heavily by interacting with it through the Sentinel Control interface.
| Capability | How it works |
|---|---|
| Escort / Standby modes | Escort makes the Sentinel follow you like a companion. Standby effectively powers it down in place, useful for settlement defense or to keep it out of build mode. |
| Loadout customization | You can equip any power armor pieces on the frame and give it any weapon (ranged or melee) from your inventory. |
| Armor durability | Power armor worn by the Sentinel does not take damage and never needs repairs while equipped. |
| Carry capacity | Like other companions, the Sentinel can carry gear for you, and calibrated shocks or carry‑weight mods on its legs apply once you exit its inventory. |
| Companion slot usage | The Sentinel is implemented as a robot; it does not occupy the normal human follower slot. You can bring it along with another companion, and perks that check for “no companion” still treat you as alone. |
| Headlamp | The Sentinel automatically switches its helmet lamp on at night and off while sneaking, in both escort and standby modes. |
One important difference from standard followers: the Sentinel can still damage you with stray shots even if you have the Inspirational perk, so high‑damage weapons and close‑quarters firefights can be risky.
Changing the Sentinel’s personality and getting the Liberty Prime voice
Personality is where this companion leans into Fallout 4’s robot flavor. When you interface with the Sentinel Control System, you can swap between several AI matrices:
- Sentry bot personality – deep, militaristic voice with heavy weapons chatter.
- Mister Gutsy personality – sarcastic soldier rhetoric with plenty of combat one‑liners.
- Assaultron personality – sharper, more clinical attack calls.
- Memory free mode – minimal or no voice lines for a quieter experience.
There is also a special Liberty Prime personality module. After finishing Malevolent Malfunction, an additional rogue Sentinel spawns in the world. It carries the Liberty Prime voice module, which lets your Sentinel roar propagandistic lines through a loudspeaker‑style filter.
That third Sentinel is encountered near Relay Tower 0BB‑915, north of Fort Hagen. Taking it down and looting the module unlocks Liberty Prime as another personality option for your companion.
Known quirks and bugs
The Sentinel Control System is powerful but not flawless. Several issues are worth calling out:
- Quest progression bugs: On some PC setups, the hidden perk that allows you to hack the Sentinel may fail to apply at the final step, leaving you unable to activate the armor. Console commands can correct this, but that is only an option on PC.
- Liberty Prime marker bug: If the Liberty Prime module is obtained before its optional objective registers properly, the map can permanently show an objective marker stuck on your own position. For PC players, more console workarounds exist; on consoles, it’s largely cosmetic but persistent.
- Inventory refresh: When you equip new power armor pieces on the Sentinel, its armor weight and carry‑weight bonuses only fully update after you exit its inventory. Sometimes this requires opening and closing the trade menu more than once.
- Stealth Boy inconsistency (PS4): On PlayStation 4, Stealth Boy armor mods behave inconsistently on the Sentinel, similar to issues seen on Chinese stealth armor when left in containers too long.
- Behavior in tight spaces: The Sentinel tends to lag behind more than human companions and can get stuck in buildings or level geometry. It also keeps following during workshop build mode unless placed in standby, which can put it directly in front of where you’re trying to construct.
Despite these quirks, the core loop works: the Sentinel follows you, soaks damage in indestructible armor, and adds extra firepower without touching your normal companion setup.
Once Malevolent Malfunction is complete and the Sentinel Control System is online, you effectively gain a second follower slot wrapped inside an autonomous power armor frame. Between that, the Outcast and Racing Stripes paint jobs, and the Liberty Prime personality module, the Creation turns a short, early‑game radio mystery into a long‑term combat asset you can theme to whatever faction fantasy you’re chasing in the Commonwealth.
