Front Trunk Open — Proceed With Caution
The TESLA-UI_A004 (Tesla) EV fault code means: Front Trunk Open — Proceed With Caution. This is a moderate severity code.
- Keep driving?
- Limited driving only
- DIY difficulty
- moderate
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What Are the Symptoms of TESLA-UI_A004?
- Alert while driving that the front trunk (hood) is open
What Causes TESLA-UI_A004? (Most Likely First)
- At least one of the two hood latches (primary and/or secondary) cannot be confirmed closed when the car is out of Park Very Likely
Can I Still Drive with TESLA-UI_A004?
Limited driving only. TESLA-UI_A004 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does Tesla alert UI_a004 mean?
Your front trunk (hood) is detected open while driving: at least one of its two latches cannot be confirmed closed.
Is it safe to keep driving?
Only until you can safely stop. Tesla recommends driving carefully, stopping, shifting into Park and closing the hood fully, because it may open while driving.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose TESLA-UI_A004?
Drive carefully until you can safely stop and shift into Park: Tesla warns the front trunk may open while driving.
Once parked, make sure the front trunk is fully closed, with both latches engaged.
The alert clears in Park but may return when you drive if the hood is not fully secured.
If it persists over multiple drives, or appears more and more often, schedule service.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- Tesla Model 3 Owner's Manual (2024+, North America, software 2026.20), Troubleshooting Alerts, printed p.286-287: UI_a004, "Front trunk open / Proceed with caution"
- Tesla alert dictionary (canonical firmware alert identifiers)community-maintained dictionary, not an official manufacturer document
Which Vehicles Commonly Get TESLA-UI_A004?
- Tesla Model 3 (RWD, Long Range AWD, Performance) -- 2017-2021 builds with MCU2
- Tesla Model Y (LR AWD, Performance) -- early production units with MCU2
- Tesla Model S (LR, Plaid) -- pre-2022 refreshed units on MCU2
- Tesla Model X (LR, Plaid) -- pre-2022 units with MCU2 and tri-screen layout
- Tesla Model 3 (RWD, Long Range AWD, Performance) -- any build after a partial OTA failure
- Tesla Model Y (LR AWD, Performance) -- units with a degraded 12V lithium accessory battery
- Tesla Cybertruck (RWD, AWD, Cyberbeast) -- MCU3 platform, less common but reported after OTA interruptions
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