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Mr. Fixed
OBD2 diagnostics made simple
Adapter disconnected (demo)
Vehicle: 2005 Chevy Silverado 4.8 V8
Modern car dashboard at night
MR. FIXED • READ. EXPLAIN. SUGGEST.

Connect to OBD Adapter

Demo connect screen. In the real app this would scan for Bluetooth / Wi-Fi OBD2 adapters like ELM327 and pair to them.

OBD2 diagnostic adapter in a vehicle
Nearby adapters (example list)
ELM327-OBDII
Standard Bluetooth adapter
OBDLink MX+
Faster, premium OBD adapter
VLink-BT
Generic ELM327-compatible dongle

Dashboard – Live Overview

Main view. In a real app, these numbers update from your OBD2 adapter while you drive.

Sports car interior at night
Car Health
84%
2 maintenance alerts • 1 stored code
Last Trip Snapshot
16.3 mpg
12.4 mi • 24 min • $0.13 / mile (est)
Live Gauges (Sample)
RPM
742 rpm
Coolant Temp
192 °F
STFT Bank 1
-2.3 %
Vehicle Speed
0 mph

Diagnostics – Trouble Codes

Layout for your code list. Real app will fill this from the truck.

Mechanic looking at car diagnostics
Code
Description
Severity
P0300
Random/Multiple Cylinder Misfire Detected
Critical
P0442
EVAP System Small Leak Detected (history)
Medium
—
No pending codes
OK
Example P0300 explanation:
  • Plain-English: Engine is missing spark/fuel randomly across cylinders.
  • Common causes: bad coils, worn plugs, vacuum leak, low fuel pressure.
  • DIY checks: inspect coils, plugs, hoses; check fuel trims & O2 sensors.
  • Fix window: 1–3 days before risking catalytic converter damage.

Mr. Fixed – Symptom Wizard

Wizard combines symptoms + codes to point at likely systems/parts in the real app.

Step 1 – What is the truck doing?
Rough idle / shaking
Feels like it wants to stall at stop lights.
Loss of power
Slow to accelerate, especially uphill or towing.
Bad MPG
You’re filling up more often than usual.
Overheating
Temp gauge climbs higher than normal or into red.
Example result – Rough idle + P0300
Likely system: Ignition system (coils, plugs, wires), with backup possibility of a small vacuum leak.

Most likely parts:
  • Ignition coil on 1–2 cylinders
  • Worn spark plugs
  • Cracked or loose vacuum hose
DIY difficulty: Medium – basic hand tools, plan 1–2 hours.

What the app guides you to do:
  • Check and swap coils to see if misfire follows
  • Inspect and replace plugs if worn
  • Check around intake / hoses for vacuum leaks

Live Data – Sensor List (Sample)

Layout for live PIDs from the OBD2 adapter.

Sensor
Value
Unit
Engine RPM
742
rpm
Coolant Temp
192
°F
STFT Bank 1
-2.3
%
Vehicle Speed
0
mph

Trips – Fuel & Driving

Example of trip logging layout based on OBD data.

Work Commute
12.4 mi • 24 min • Yesterday 7:42 AM

16.3 mpg
0.74 gal • $2.12 est • 4 hard accelerations • 2:31 idle
Town Run (Errands)
8.3 mi • 32 min • 2 days ago

14.1 mpg
Stop-and-go traffic • more idle time
Test Drive After Coil Swap
5.1 mi • 10 min • 3 days ago

17.8 mpg
No misfires detected • trims within ±3%