U3003: How to Diagnose & Fix — Battery Voltage
4 vehicles · 2 makes · $100-$900 repair
How to diagnose and fix U3003: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Ford Bronco Sport · 2021–2024
NHTSA recall 24V267000 (Ford reference 24S24) covers 456,565 model year 2021-2024 Bronco Sport and 2022-2023 Maverick vehicles. The Body Control Module and Powertrain Control Module fail to detect 12V battery degradation, resulting in loss of motive power whenever an Auto Stop/Start event occurs or during low-speed braking. Two follow-up campaigns address inadequate initial remedies: 25S02 (NHTSA 25V019, January 2025) replaced defective Camel EFB batteries with Ford AGM units on 272,817 vehicles, and 25S26 (NHTSA 25V158, March 2025) re-fixed 48,041 vehicles previously repaired incorrectly. Dealers reflash control modules and/or replace the battery free of charge.
Common Symptoms
- Vehicle stalls at low speeds or when coming to a stop
- Engine does not restart after Auto Start-Stop activates
- Loss of interior lights and accessories when stalling
- Air conditioning cuts out unexpectedly
- "Remote Access disabled to reserve battery" alert in FordPass app
- Battery warning light
- No-start condition
How to Fix
Ford Safety Recall 24S24 - free software update at any Ford dealer for BCM and PCM. Takes approximately 1-2 hours. Check fordowner.com or safercar.gov with VIN for recall status. If experiencing stalling or no-restart issues before recall service: disable Auto Start-Stop feature (button typically near shifter). Replace 12V battery if it is weak or over 3 years old as preventive measure.
Sources for this issue (5)
- Ford Recall 24S24 - Bronco Sport and Maverick Loss of Powerrecall
- NHTSA Part 573 Safety Recall Report 24V-267 (Ford 24S24)recall
- NHTSA Recall 25V-019 (Ford 25S02) - 12V battery replacementnhtsa
- NHTSA Recall 25V-158 (Ford 25S26) - incorrect 24V-267 repairsnhtsa
- NHTSA Recall API - Ford Bronco Sport (Campaign 24V267000)nhtsa
Mazda CX-30 · 2020–2021
Mazda issued Special Service Program SSPC5 for the CX-30 covering multiple control-module reprogramming concerns, the first of which is a battery concern: the climate control unit (CCU) and body control module (BCM) may not transition into sleep mode after the ignition is switched OFF. The modules stay awake and draw current continuously, flattening the 12V battery over a few days of non-use. Owners report the low-battery warning after short parking periods, no-start conditions, and in several documented cases repeated tow-ins with batteries that still pass Mazda's own load specification - the classic signature of a parasitic draw rather than a failed battery. SSPC5 covers 2020-2021 CX-30s built from September 26, 2019 through September 10, 2020, and the i-stop system's sensitivity to state of charge makes the symptom show up early as i-stop simply refusing to work. Note this is distinct from recall 25V357, which concerns what the air bag sensor does after a battery is already dead.
Common Symptoms
- Battery management low-charge warning message after the car sits a few days
- No-start or slow crank after short periods of non-use
- i-stop auto start-stop stops functioning
- Repeated battery replacements that do not cure the problem
- Battery tests good but goes flat again
- Electrical accessories reset or behave erratically after a flat battery
How to Fix
For vehicles covered by SSPC5, Mazda dealers reprogram the CCU and BCM (a module software update performed with Mazda's M-MDS diagnostic system) free of charge; U.S. owners were notified by mail no later than April 17, 2021. This is a Special Service Program, not a safety recall, so it is not VIN-searchable on NHTSA - ask the dealer to check SSPC5 eligibility by VIN. For vehicles outside the program, have a parasitic draw test performed with the modules allowed to time out before condemning the battery; many owners report the drain warning stops after fitting a higher-quality replacement battery, but that treats the symptom rather than the module sleep fault.
Sources for this issue (5)
- Mazda Special Service Program SSPC5 - Multiple Control Module Reprogramming (NHTSA MC-11003695)tsb
- SSPC4 and SSPC5 Recall and Special Program information - Mazda CX-30 Forumforum
- BATTERY Drain Issue Special Service Program NEW - Mazda CX-30 Forumforum
- Battery Drain (Dead Battery) - Mazda CX-30 Forumforum
- Rapid battery discharge - Mazda CX-30 Forumforum
Ford Bronco · 2021–2024
A recurring owner complaint on newer Broncos is unexpected battery discharge after sitting, sometimes leading to a no-start condition, multiple warning messages, or modules behaving erratically. Reports often mention the vehicle being parked for only a few days before the battery is too weak to crank, with some cases linked to software/module sleep issues or accessory loads. The problem is documented in owner forums and complaint databases, though root causes can vary by vehicle.
Common Symptoms
- Dead battery after sitting
- No-start or slow crank
- Multiple warning lights on startup
- Remote functions inoperative
- Infotainment glitches after low voltage
How to Fix
Load-test the battery first, then check charging system output and perform a parasitic draw test after all modules should be asleep. Verify BCM/APIM/FDRS software is current and inspect aftermarket accessories, dash cams, and poorly wired add-ons. In some cases, replacing a weak factory battery and updating modules resolves repeat no-start events.
What you need to diagnose it
The fix here starts with a test, not a part — which repair you need depends on what the test finds.At least one code uses a manufacturer-specific format. No scanner recommendation is shown because family-level coverage cannot prove it can read that code.
UNI-T UT210E Low-Current DC Clamp Meter
1 mA resolution on the 2 A range — a 0.1 A meter reads a 50 mA drain as zero
$40–$70View
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
Testing and isolating the fault is DIY work. Replacing or reprogramming a control module is not — most are VIN-programmed, so a new one does nothing until a shop codes it to your car. Check for an open recall or service bulletin before buying anything.
Sources for this issue (1)
Ford Explorer · 2016–2020
Find U3003 by make
Browse every documented model and issue for your make.
U3003 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U3003 mean?
U3003 stands for "Battery Voltage." U3003 is a generic code meaning a control module detected that its supply (battery/system) voltage was outside its normal operating range — either too low or too high. Modules need a stable voltage (roughly 12 to 14.5 volts) to work reliably, and out-of-range voltage can cause erratic module behavior and set this code. It is frequently a symptom of a weak battery or charging-system problem rather than a fault in the module itself.
What are the most common causes of U3003?
The most common causes of U3003 are: Weak, discharged, or failing battery, Faulty alternator / charging system (under- or over-charging), Corroded or loose battery terminals or cables, High-resistance ground or power connections, Poor module power/ground circuit, Excessive parasitic draw, Voltage drop from corroded fuse box or connectors. The specific cause varies by vehicle.
How much does it cost to fix U3003?
Repair costs for U3003 range from $100 to $900, depending on the vehicle and root cause.
Which vehicles are affected by U3003?
Au7o has documented U3003 across 4 vehicle models from 2 manufacturers: Ford, Mazda.
Join 600+ people using Au7o to better understand their vehicles.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.