OBD2 Cat vs OBD Vault
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
OBD2 Cat
This app reads diagnostic trouble codes and live vehicle data from compatible cars using a Bluetooth OBD2 adapter. It helps drivers understand dashboard warnings by checking engine codes, viewing sensor data, and retrieving vehicle identification information.
- Read diagnostic trouble codes (DTCs)
- Clear supported trouble codes
- View live engine and sensor data
- Check VIN, make, model, and year
- Auto Scan for codes
- View OBD protocol and connection status
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Your car has a story. OBD2 Cat helps you read the clues. OBD2 Cat is a straightforward Bluetooth OBD2 car scanner for compatible vehicles and adapters. Read diagnostic trouble codes, view live vehicle data, and check key vehicle details from your iPhone. With OBD2 Cat, you can: - Read Check Engine diagnostic trouble codes (DTCs) - Clear supported trouble codes - View supported live engine and sensor data - Check and copy your VIN, plus available make, model, and model year - Turn on Auto Scan to scan for codes after connecting - See the active OBD protocol and connection status Designed for drivers who want a simple first look when a dashboard warning appears, without the clutter of a professional workshop tool. Use a Bluetooth OBD2 adapter compatible with your iPhone and vehicle. If you use an ELM327-style adapter, make sure it supports Bluetooth Low Energy (BLE). Important: Clearing a trouble code does not repair the underlying issue. A warning light may return if the fault remains. For safety-critical warnings or persistent problems, have the vehicle inspected by a qualified technician.
OBD Vault
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OBD Vault reads vehicle data through a compatible ELM327 Bluetooth Low Energy (BLE) or Wi-Fi/TCP OBD-II adapter. An adapter and a vehicle are required for live readings and new scans. Bluetooth Classic adapters are not supported on iPhone. Available readings depend on your vehicle, ECU and adapter. Wi-Fi recording requires OBD Vault to remain open with the screen on; it pauses when you leave the app or lock the screen. You can keep the Live Data screen open while recording. SCAN AND UNDERSTAND Read confirmed, pending and permanent diagnostic trouble codes, supported sensor readings and emissions readiness information. Review stored freeze-frame data when the ECU provides it. Code explanations and suggested checks are guidance; they do not identify a confirmed root cause or certify that a vehicle is safe to drive. LIVE DATA AND TRIPS View supported live readings such as engine RPM, speed and coolant temperature. Record trips, review distance and sensor history, and keep diagnostic scans separate from trip records. View ECU-reported fuel flow when supported, or an estimate when the required readings and fuel profile are available. Recalculate estimated fuel use for saved trips when the necessary sensor history was recorded. VEHICLE PROFILE When VIN is unavailable, optionally select your make, model and engine before your first scan. Search an offline catalog of 433 makes and 10,871 models. Engine choices are tied to the selected model and show capacity, fuel and available power. Manual entry remains available for missing variants. YOUR HISTORY, OFFLINE Save scans and trips on your phone without an account. Review saved history locally. File export requires active paid access. Clearing fault codes is a separate manual action that requires confirmation and shows the ECU response. VEHICLE PLANS, CLOUD AND YOUR OWN AI Local scanning, live data and history for one vehicle are free. Paid plans cover a total of 1, 3 or 10 vehicles and include cloud synchronization, access from your own AI assistant through Model Context Protocol (MCP), and file exports. Choose monthly, annual or lifetime access. Monthly and annual subscriptions renew automatically until canceled in your store account. Lifetime is a one-time purchase. Current prices and purchase terms are shown in the app. Sign in to synchronize saved records across devices. Your external assistant and account must support adding an MCP connector; set up that connection separately in your assistant. The app shows setup guidance after your first successful scan. OBD Vault does not run an AI model, and its connector cannot send commands to your vehicle. OBD Vault supports standard OBD-II diagnostics and selected manufacturer-specific control units and readings where a supported reference is available. Coverage depends on your vehicle, ECU and adapter. It does not provide comprehensive manufacturer coverage, ECU coding or active tests. It is not a replacement for inspection or advice from a qualified technician. Vehicle data by VehiclesDB (vehiclesdb.com). Additional source data: FuelEconomy.gov (DOE/EPA) and European Environment Agency. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is in-app purchases: OBD2 Cat at none against OBD Vault's 9. OBD Vault's advantage is update cadence (weekly vs fortnightly). On price, ads, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. OBD Vault sells 9 in-app purchases, starting at $2.99 per month. OBD2 Cat asks for nothing beyond the download.
OBD2 Cat ships an update fortnightly, OBD Vault weekly. The most recent releases landed on October 30, 2026 and October 31, 2026 respectively.
| Parameter | OBD2 Cat | OBD Vault |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Number of ratings | 1 — better | — |
| Update frequency | Fortnightly | Weekly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone | iPhone, iPod — better |
| Requires iOS | 16.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 15 MB | 41 MB |
| Age rating | 4+ | 4+ |
| Developer | Roman Tikhonychev | Bahdan Hal |
In-app purchases
OBD2 Cat
No in-app purchases
OBD Vault
- 1 vehicle · Per month$2.991 Month
- 3 vehicles · Per month$5.991 Month
- 10 vehicles · Per month$14.951 Month
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- 1 vehicle · Per year$17.991 Year
- 3 vehicles · Per year$35.991 Year
- 10 vehicles · Per year$89.991 Year
- 1 vehicle · Lifetime$34.99
- 3 vehicles · Lifetime$69.99
- 10 vehicles · Lifetime$174.99








