Scan any used car with your phone + a $15 OBD2 dongle. Get a plain-English health report before you buy - no mechanic needed.
A mechanic and auto shop owner posted car-buying tips on Reddit. It got 71,946 upvotes and 1,821 comments - one of the most upvoted posts in r/LifeProTips history. The demand was so overwhelming that the OP started building an app himself (carprocheck.com).
Real people asking for this
LPT: Some tips for buying a used car for people that know nothing about cars
I am a mechanic/auto shop owner. After getting so much continued feedback from this post, I have decided to make an app to help people when purchasing vehicles. I am hoping to put something together that gives you tips and helps pull the OBD2 data in an easy to interpret way.
The core insight: every used car buyer should get a pre-purchase inspection, but most people skip it because it costs $150-300 and requires scheduling with a shop. Meanwhile, a $15 Bluetooth OBD2 dongle can read engine codes, sensor data, and system health - but the raw data is incomprehensible to anyone who isn't a mechanic.
Build a mobile app that connects to any ELM327 OBD2 adapter via Bluetooth. Run a full diagnostic scan. Then translate the results into plain English: "Engine: healthy, no fault codes. Transmission: 2 minor sensor warnings - not urgent but negotiate $200 off. Battery: weak, likely needs replacement within 6 months ($150-200)." Add a used car buying checklist with photo documentation - rust spots, tire tread depth, fluid colors.
The app becomes the buyer's advocate. Before you hand over $15,000 for a used Camry, spend 10 minutes scanning it. The report either gives you confidence or saves you from a lemon.
Freemium model: free basic scan (check engine light yes/no). $4.99/scan for full diagnostic report with plain-English interpretation. $29.99/year unlimited scans for dealers and frequent buyers. Bundle with a branded OBD2 dongle for $39.99 (dongle + 5 scans included).
At 100,000 paid scans/year at $5 average, that's $500K. Add 10,000 annual subscribers at $30, that's another $300K. The 72K-upvote post proves the demand exists at massive scale. The OP validating by building it himself is the strongest signal possible.
Analysis and revenue estimates are educational. Results vary by execution and market conditions.
Quick breakdown
Used car buyers with no mechanical knowledge - first-time buyers, parents buying for kids, anyone spending $5K-30K on a used vehicle
FIXD ($25 device + $10/mo app, basic code reading), Carly ($60/yr, enthusiast-focused), Torque Pro ($5, raw data only for gearheads), CarFax (history report, no live diagnostics), professional inspections ($150-300)
72K upvotes proves massive demand. No app translates OBD2 data into plain English for non-mechanics. FIXD is closest but focuses on your own car, not pre-purchase. $15 OBD2 dongles are commoditized - the value is in interpretation.
Mobile app with Bluetooth OBD2 connection. Scan, interpret results in plain English, generate shareable report. Add photo checklist for visual inspection. Launch on the carprocheck.com waitlist audience + r/usedcars and r/whatcarshouldIbuy.
MVP Features
Revenue Potential
$500K - $2M
Execution Difficulty
Medium
Competition
Medium competition
Type
Mobile App
Market
B2C
Target
Used car buyers with no mechan
Competition
Medium
monthly searches
Source
Discovered from Reddit via AI analysis. Validated with 2.4K/mo search demand.