Comparison

Giotto ScanTool vs DiagonalOBDII

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Giotto ScanTool

This professional-grade automotive diagnostic tool provides extensive vehicle coverage and deep system access. It helps repair shops and fleet managers quickly service a wide range of vehicles with features like live data, bi-directional controls, and DTC reporting.

Highlights
  • Professional-grade enhanced coverage
  • Access to ABS, airbag, powertrain, and more
  • Live data and bi-directional controls
  • Adaptive resets and learns
  • DTC report output (XML/PDF)
  • Graphing with pan and zoom
  • WIFI connectivity
Features
Read full description

Requires an AutoEnginuity Proline VCI WIFI, available for purchase at www.AutoEnginuity.com. Does not support other hardware. Coverage, coverage, coverage. In the professional repair business getting as much coverage as you can is important to effectively and quickly service any vehicle. We offer professional-grade enhanced coverage options for 58 carmakers. It’s not just the breadth of coverage that’s important—it’s also the depth of coverage. With our enhanced expansions you can have access to ABS, airbag, enhanced powertrain, instrument cluster, transmission, and dozens of other body and chassis controllers. The depth of coverage consists of live data, bi-directional controls, adaptive resets and learns, system tests, and trouble code retrieval and clearing. Whether your a fleet manager, independant repair shop, or a collision repair shop, Giotto will help repair more vehicles quickly and effectively. Powerful features include: DTC report output (XML / PDF), Mode 6 translations, graphing with pan and zoom, integrated FF and FFD (odometer, fault frequency, etc.) with DTC reports, and easy to use WIFI connectivity. *NOTE* Enhanced coverage requires activated ProLine hardware.

About

DiagonalOBDII

This app helps mechanics perform vehicle drive cycles more efficiently. It provides real-time monitoring of emissions monitors and diagnostic trouble codes (DTCs), offering clear guidance and instant explanations to ensure vehicles pass inspection quickly and accurately.

Highlights
  • Live drive cycle monitoring
  • Immediate diagnostic trouble code (DTC) identification
  • Real-time emissions monitor status
  • Precise drive cycle parameter guidance
  • Professional, easy-to-navigate dashboard
  • Instant code explanations
Read full description

Diagonal is designed specifically for mechanics who want to simplify and speed up vehicle drive cycles. Instantly track emissions monitors and diagnostic trouble codes (DTCs) live, ensuring accurate diagnostics and rapid vehicle readiness for inspection. Key Features: -Live Drive Cycle Monitoring: Clearly see the real-time status of emissions monitors as they run, complete, or require further action during your drive. -Immediate Diagnostics: Quickly identify and address active trouble codes (DTCs) as they appear, eliminating uncertainty during drive cycles. -Efficiency and Accuracy: Avoid unnecessary repeat drive cycles by verifying real-time monitor completion, ensuring vehicles pass inspection on the first try. -Precise Drive Cycle Guidance: Monitor essential drive cycle parameters such as speed, RPM, engine temperature, and throttle position to meet exact diagnostic requirements. -Professional Dashboard: Access all critical information quickly through a clear, easy-to-navigate interface tailored for automotive professionals. -Instant Code Explanations: Quickly interpret trouble codes with straightforward, mechanic-friendly explanations. Why Mechanics Trust Diagonal: -Saves Valuable Time: Complete diagnostic drive cycles accurately the first time. -Faster Inspections: Immediately identify vehicle readiness to streamline your workflow. -Reduces Diagnostic Uncertainty: Clear, actionable data presented in real-time. -Diagonal empowers professional technicians with the tools to perform diagnostics faster and more efficiently than ever before. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://diagonal-d070c.web.app/privacy.html

Screenshots

Giotto ScanTool4 screens
DiagonalOBDII4 screens

Verdict

The call

The clearest difference is rating: DiagonalOBDII at 5.0 against Giotto ScanTool's 3.3. DiagonalOBDII also leads on update cadence (every 2 weeks vs every 3 months). Giotto ScanTool's advantage is in-app purchases (none vs 4) and review sentiment (31% vs 0%). On price and ads 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. DiagonalOBDII sells 4 in-app purchases, starting at $12.99 per month. Giotto ScanTool asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

DiagonalOBDII holds the better App Store score, 5.0 against 3.3. That said, the two scores are not equally well evidenced: Giotto ScanTool has 44 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 31% of Giotto ScanTool's written reviews are positive against 0% of DiagonalOBDII's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Giotto ScanTool ships an update every 3 months, DiagonalOBDII every 2 weeks. The most recent releases landed on June 1, 2026 and August 22, 2026 respectively.

Scorecard8 real differences · 2 level
Giotto ScanTool versus DiagonalOBDII: the parameters behind the verdict, then further details
ParameterGiotto ScanToolDiagonalOBDII
PriceFreeFree
Rating3.3 (44 ratings)5.0 (1 ratings) — better
Positive reviews30.8% of reviews — better0.0% of reviews
Number of ratings44 — better1
Update frequencyEvery 3 monthsEvery 2 weeks — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPad, iPod — betteriPhone
Requires iOS14.0 — better18.1
Further details — not scored
Size912 MB21 MB
Age rating4+4+
DeveloperAutoEnginuityKyle Louderback

Customer experience

Giotto ScanTool

All ratings44 ratings
Positive59.1%
Neutral2.3%
Negative38.6%
Written reviews13 reviews
Positive30.8%
Neutral0.0%
Negative69.2%

DiagonalOBDII

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

In-app purchases

None

Giotto ScanTool

No in-app purchases

4 purchases

DiagonalOBDII

Subscriptions4
  • Diagonal Premium Monthly$12.991 Month
  • Diagonal Premium Trial1 Month trial$12.991 Month
  • Shop Owner - Monthly$17.991 Month
Show 1 more
  • Diagonal Premium Yearly$99.991 Year

Questions

Is Giotto ScanTool free?
Giotto ScanTool is free to download, with no in-app purchases.
Is DiagonalOBDII free?
DiagonalOBDII is free to download, with in-app purchases available.
Which has better reviews, Giotto ScanTool or DiagonalOBDII?
DiagonalOBDII is rated higher. Giotto ScanTool averages 3.3 out of 5 from 44 ratings, while DiagonalOBDII averages 5.0 from 1 ratings.
Do Giotto ScanTool or DiagonalOBDII have ads?
Neither Giotto ScanTool nor DiagonalOBDII shows ads.
Which is updated more often, Giotto ScanTool or DiagonalOBDII?
Giotto ScanTool ships an update every 3 months, and DiagonalOBDII every 2 weeks. Most recently, Giotto ScanTool was updated on June 1, 2026 and DiagonalOBDII on August 22, 2026.

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