⚙ Free Diagnostic Tool

Decode Your
Check Engine Light

Enter any OBD fault code. Get a plain-language explanation, ECU technical breakdown, symptoms, and step-by-step DIY fixes — free, no app required.

Press Enter to search · Supports P, B, C, U codes  ·  3,722+ codes in database

3,722+
OBD Fault Codes
P B C U
All Code Systems
Free
No App Required
🌍
Works Worldwide

🔥 Most Common Fault Codes

📂 Browse by System

⚙️
Powertrain (P)
P0xxx – P3xxx codes
💺
Body (B)
Airbag, windows, locks
🛞
Chassis (C)
ABS, traction, steering
📡
Network (U)
CAN bus, module comms
🔧
Chassis/Safety
1,481 codes
🔧
Network/Communication
533 codes
🔧
Transmission Control
490 codes
🔧
Fuel and Air Metering
379 codes
🔧
Emission Controls
276 codes
🔧
Engine Cooling
209 codes
🔧
Ignition System
179 codes
🔧
Speed/Idle Control
156 codes

🛠 How This Tool Works

01
Scan Your Vehicle
Use any OBD-II scanner (or a free app like Torque Pro) on your car's OBD port (under the dashboard). Note the fault codes shown.
02
Enter the Code Here
Type the code (e.g. P0420) into the search box above. Our database covers 10,000+ generic and manufacturer-specific codes.
03
Read the Plain-Language Report
Get a human-friendly explanation, ECU threshold data, symptoms checklist, and a prioritised fix guide — no mechanic jargon.
04
Fix or Inform Your Mechanic
Use the DIY guide to attempt simple fixes yourself, or share the technical breakdown with your mechanic for faster, accurate service.
ℹ️

Disclaimer & Safe Use

This tool provides diagnostic information for reference purposes. OBD-II codes indicate a fault was detected by the ECM but do not pinpoint the exact failed component — they identify the system or circuit that is out of specification. Always verify diagnosis with live sensor data before replacing parts. For safety-critical systems (brakes, airbags, steering), consult a certified mechanic. Motoautiv is not liable for repairs undertaken based solely on this tool.