Welcome to DTC Helper
Your Diagnostic Trouble Code Assistant
Is your check engine light on? Don’t panic. At DTC Helper, we make it easy to understand what’s going on under the hood. Whether you’re a DIY car owner or an automotive professional, our tools and guides help you decode DTC (Diagnostic Trouble Codes) quickly and accurately.
What Is a DTC?
DTCs (Diagnostic Trouble Codes) are alphanumeric codes that your vehicle’s onboard computer generates when it detects an issue. These codes are the key to diagnosing everything from minor sensor glitches to serious engine problems.
But here’s the problem: most car owners don’t know what a code like P0420 or U0101 really means or how to fix it.
That’s where we come in.
What We Do at DTC Helper
Why Trust Us?
We research each DTC using industry-grade databases and verified technician input. Our content is constantly updated to reflect modern vehicles and repair trends.
You’re not getting AI-generated fluff you’re getting real insight.
Who Is DTC Helper For?
DIY car owners – Fix your own car with confidence.
Mechanics & technicians – Quick code references and resources.
Used car buyers – Decode check engine lights before you buy.
Auto students – Learn how real-world diagnostics work.
Explore Our Tools
DTC Lookup Tool – Instantly decode any OBD-II code
Fix Guides by Code – Learn how to repair issues from P0101 to P2195.
Blog & Help Center – New guides every week.
Mobile Friendly – Use on your phone while working on your car.
How to Use DTC Helper
Using DTC Helper is simple:
Plug an OBD-II scanner into your car.
Get the code shown (e.g., P0300).
Enter it into our search tool or browse by category.
Read the meaning, causes, symptoms, and fixes.
Decide if it’s a DIY job or time for a mechanic.
From the Garage: Expert Tips & DTC Fixes
Stay informed with practical guides, real-world diagnostics, and step-by-step fixes for common trouble codes. Whether you’re facing P0171 or just curious about how OBD-II systems work, our blog has you covered.
P0300 – Random/Multiple Cylinder Misfire Detected: Meaning, Causes & How to Fix
When your car’s engine starts shaking, stalling, or the check engine light flashes rapidly, one of the most dreaded OBD2 codes appears: P0300.
P0300 – Random/Multiple Cylinder Misfire Detected: Causes, Symptoms & Fixes
Seeing a check engine light with the code P0300 can feel alarming especially since it refers to random or multiple misfires occurring in your engine.
P0420 – Catalyst System Efficiency Below Threshold (Bank 1): Causes, Symptoms & Fixes
Code P0420 is one of the most common and confusing check engine light triggers. It refers to the catalytic converter’s efficiency dropping below the threshold on Bank 1 of your engine.
P0171 – System Too Lean (Bank 1): Causes, Symptoms, Diagnosis & Repair Guide
If your check engine light is on and your scanner throws the code P0171, you’re dealing with a very common and potentially frustrating engine issue: a “lean” fuel mixture on Bank 1 of your engine.
P0420 Code – Meaning, Causes, Symptoms & Fixes
The P0420 trouble code is one of the most common OBD-II codes that vehicle owners and technicians encounter. It refers to an issue related to the catalytic converter system an essential part of a car’s emissions control.
P0300 Code – Causes, Symptoms, and How to Fix Engine Misfires
The P0300 trouble code is one of the most common and frustrating diagnostic trouble codes (DTCs) that vehicle owners and mechanics encounter.
What Our Users Say
Join thousands of car owners and mechanics who trust DTC Helper to decode engine trouble codes and find real solutions fast. Here’s what a few of them had to say.
Contact & Support
Questions, suggestions, or correction tips? Contact us here we’d love to hear from you.