Your car is talking.
CarStem helps you understand it.
AI-assisted interpretation, live OBD2 telemetry, vehicle-specific repair guidance, cost context and roadside tools — one persistent intelligence layer for the car you actually own.
Connect compatible OBD2 hardware for live evidence or start without it. CarStem combines symptoms, vehicle history and model-specific knowledge to turn warning signs into clear next steps.
Reads what the ECU is doing
Compatible OBD2 telemetry turns the car itself into evidence.
Builds your car's baseline
Idle, cruise, load and restart behavior become individual context over time.
Connects the evidence
Telemetry, symptoms, service history and vehicle knowledge reason together.
Know what deserves action
Understand urgency, likely causes, next steps and what still needs verification.
Features you won't find anywhere else.
See Where to Inspect
and What a Serviceable Reference Looks Like
When the evidence supports a visual target, CarStem can show a vehicle-specific inspection reference and a comparison where it can do so truthfully. Generated visuals help you orient yourself to the affected system; they do not prove that the pictured component failed.
Stranded? CarStem Has
Your Back — Instantly.
One tap activates SOS Emergency Mode. CarStem uses the vehicle evidence and details available to you, gives step-by-step guidance, and can use optional location to help you find nearby assistance. It explains what the available evidence suggests you should do next without pretending the app can physically inspect the scene.
Pull over safely. Turn off the engine. Do NOT open the hood for 30 minutes.
Your mechanic meets your car today.
CarStem can remember yesterday.
The longer you own a vehicle, the more context exists. CarStem is designed to keep that context useful instead of letting it disappear between warning lights, repairs and shop visits.
The warning light comes after the uncertainty.
The stressful part is not the icon on the dash. It's not knowing what changed, how serious it is, or whether yesterday's behavior matters.
A repair decision without context is expensive.
When you do not know your vehicle's history, likely causes or fair next step, every recommendation feels like a guess you have to pay for.
Generic answers don't know your car.
The same model can age differently. CarStem's advantage grows as model knowledge, service history and your own vehicle evidence accumulate.
Home → Live → Ask → Care
Build the vehicle context
Add your exact vehicle. CarStem organizes its history and source-backed model knowledge separately, preserving where each fact came from.
Let CarStem learn your car
With compatible OBD2 hardware, Live captures real ECU signals and learns how your individual vehicle behaves at idle, cruise, load, warm restart and more.
Ask CIC what it means
CIC reasons across current readings, learned behavior, issue and service history, and source-backed vehicle knowledge — while keeping evidence types distinct.
Bring your vehicle into CarStem.
CarStem works as an ownership-intelligence platform without an adapter. A compatible OBD-II adapter unlocks live ECU data, drive intelligence, diagnostic evidence and vehicle-specific learning.
Veepeak OBDCheck BLE
CARSTEM VERIFIEDThe adapter currently proven end-to-end with CarStem during real vehicle testing.
Bluetooth LE · ELM327 v1.5 · iOS / Android / Windows / Mac
Veepeak OBDCheck BLE+ Plus
COMPATIBILITY PENDINGHardware specifications fit CarStem's BLE architecture, but this exact model has not completed CarStem physical verification yet.
Bluetooth LE · ELM327 v2.2 · iOS / Android / Windows / Mac
Verified means tested
We don't call hardware CarStem Verified until we've physically proven it.
Web access today
CarStem is currently accessed through its web experience. Live Bluetooth capability depends on the device and browser environment.
Native apps are next
iPhone and Android releases are in development. CarStem is not currently listed in the App Store or Google Play.
Buying an adapter? Choose a CarStem Verified model for the most certain experience today. Compatibility varies by vehicle, adapter capabilities and the data individual ECUs expose.
Everything you need to own a car with confidence.
Six tools, one app. Built for real car owners — not mechanics.
Weekly Car Checks
Get a weekly evidence summary for the systems CarStem has actually observed, including what changed, what deserves attention, and what remains unknown.
Fair Repair Cost Estimates
See an evidence-backed repair-cost range before you go to the shop, with the limits and variables made clear.
Maintenance History Vault
Keep oil changes, tire rotations, repairs, documents, and service history together so you can review what happened and when.
Fuel + Trip Logs
Track fill-ups and preserve drive or mileage records for ownership and business recordkeeping. Review exported records before relying on them for tax reporting.
Pre-Sale Reports
Planning to sell? Generate a clean vehicle-history report that helps a buyer understand the evidence you chose to document.
Mechanic Visit Companion
Go into a shop visit with your vehicle evidence, useful questions, and a clearer understanding of what still needs to be verified.
A scanner reads the car. CarStem learns it.
CarStem combines live vehicle evidence, learned behavior, ownership history and source-backed vehicle knowledge so CIC can reason from more than a single code or snapshot.
Hardware is optional for many ownership tools. Compatible OBD2 hardware unlocks the individual-car learning layer.
Useful answers without pretending to know more than the evidence.
Unknown stays unknown
If CarStem cannot observe or verify a system, it does not quietly label it healthy. Coverage and confidence are shown as scoped evidence, not whole-car certainty.
A code is evidence — not a parts cannon
DTCs are interpreted against the vehicle and strongest available source. A code can identify an affected system without pretending one physical component is already proven failed.
AI has visible boundaries
AI helps explain, research and organize evidence. Generated guidance and visuals are labeled as references when they are not direct physical proof of your exact vehicle condition.
Less Guessing. Better Context. Smarter Decisions.
CarStem helps you understand evidence, compare options, and make better-informed ownership decisions.
Instant clarity, zero cost
- AI-assisted issue explanations (2 per day)
- Drivability guidance from available evidence
- Recall alerts
- 2 full vehicle scans per month
- Sound issue detection (basic)
- Unlimited scans
Take control of your car
- Everything in Free
- Unlimited scans
- Full repair guidance (DIY + shop prep)
- Repair-cost context and quote comparison
- Weekly insights + maintenance horizon
- Car history tracking
Optimize every decision. Save the most.
- Compare repair paths and available cost context
- Explore repair-vs-wait scenarios with stated assumptions
- Explain and compare itemized repair quotes
- Generate organized vehicle and incident reports
- Decide whether to fix or sell your car
- Monitor evidence changes across drives and service history
Full Pro access. Cancel anytime.
Repair decisions are easier when you can see the evidence, the uncertainty, and the available cost context.
Try Pro free for 7 days and decide whether the added vehicle intelligence is useful to you.
Built for drivers who want evidence before guesswork
Common questions.
Useful intelligence without hiding how it works.
CarStem needs context to be useful. We explain what context is used, why it is used, when outside services are involved, and where the evidence stops.
Your vehicle data stays tied to your garage
CarStem can store the vehicle details, OBD/ECU evidence, drive history, service records and files you choose to add so the app can remember your car over time. We do not sell your personal or vehicle data to advertisers or data brokers.
AI is used openly — not invisibly
CarStem uses AI for plain-English explanations, repair guidance, document or image analysis, and some research tasks. Relevant vehicle context may be sent to AI service providers to perform those requests. AI output is assistance, not proof that a component failed.
Location is optional
If you allow it, location can support SOS/nearby help, regional cost context and local weather. Precise coordinates are not saved to your persistent vehicle history; derived weather observations may be retained with drive evidence to explain operating conditions.
Evidence has boundaries
Vehicle sensors outrank weather. Missing data stays unknown. A DTC identifies what an ECU reported, not automatically the failed part. Generated issue visuals are inspection references, not photographs proving your vehicle's condition.