Car Fault Code Reader

Car Fault Code Reader

Has the dreaded engine check light just appeared on your dashboard? A car fault code reader is an essential tool for all UK drivers to quickly read and clear error codes when that happens.

This comprehensive guide explains what car fault code readers are, how they work, their key benefits, top picks for DIYers and professional mechanics, and tips for how to use OBD2 scanners to diagnose and resolve engine problems.

What is a Car Fault Code Reader?

A car fault code reader, also known as an OBD2 scanner, is a diagnostic device that plugs into your vehicle’s on-board diagnostics (OBD) port. It scans for and reads any engine fault codes stored by your vehicle’s computer, then displays the associated error messages to help you pinpoint any mechanical or electrical issues.

The check engine light appears when your car’s OBD system detects a malfunction and stores a diagnostic trouble code (DTC). Fault code readers allow you to extract these codes to understand what triggered the light and identify failing components. This enables faster diagnosis so you can get your car fixed promptly.

How Do Car Fault Code Readers Work?

Fault code readers work by hooking up to your car’s OBD2 port, which is usually located under the steering column. The scanner will power on and link to your vehicle’s computer network. It will scan all control units to pull DTCs and show the code along with an error message.

For example, code P0302 means a cylinder 2 misfire was detected. The scanner may also display “live data” like engine parameters in real time. Basic fault code readers just read and clear generic codes, while more advanced professional-grade scanners offer manufacturerspecific codes and enhanced bi-directional functionality.

How Do Car Fault Code Readers Work?
How Do Car Fault Code Readers Work?

Benefits of Using a Car Fault Code Reader

There are many advantages to keeping an OBD2 fault code scanner in your car. Benefits include:

  • Read and understand check engine light warnings immediately
  • Faster diagnosis of issues down to the failing component
  • Avoid guesswork when ordering parts or describing problems
  • Perform some functionality tests for sensors and actuators
  • Identify minor problems before they become major repairs
  • Monitor vehicle health between professional service intervals
  • Clear generic DTCs and turn check engine light off after repairs
  • Reduce trips to the mechanic for basic diagnostic scans
  • Avoid getting overcharged for repairs you can do yourself

Having the ability to self-diagnose issues using an OBD2 scanner offers convenience, saves money, and provides peace of mind between garage visits.

Top Car Fault Code Readers for DIY Use

There are many excellent car fault code readers for sale in the UK targeted at everyday drivers. The top-rated budget-friendly OBD2 scanner picks include:

Ancel AD310 Diagnostic Scan Tool

  • Read and clear generic and some manufacturer codes
  • Live data stream capabilities
  • Rugged design with large color display
  • Excellent value under £20

Foxwell NT301 OBD2 Scanner

  • Well-known brand in DIY scan tools
  • Reads and resets engine, ABS, airbag codes
  • Oil light and battery reset functions
  • Durable build quality with clear LED display
  • Established OBD2 scan tool manufacturer
  • Quickly scans and erase generic codes
  • Built-in code lookup library
  • Clear LCD screen and one-click refresh

BlueDriver Bluetooth Scanner

  • Connects wireless to smartphone app
  • Used by many UK auto enthusiasts
  • Live sensor data, relearn readiness monitors
  • Provides RepairPal report for diagnostics

Top Professional-Grade Car Fault Code Readers

Professional mechanics rely on advanced OBD2 scanners with full capabilities. The best commercial-duty code readers in the UK include:

Autel MaxiSys Ultra

  • Flagship model supports all systems and codes
  • Complete functionality for diagnostics and programming
  • 10-inch touch screen with fast quad-core processing
  • Wireless and cloud capabilities

Bosch KTS 590

  • Trusted Bosch engineering and quality
  • Complete European, Asian, American vehicle coverage
  • Fast performance with intuitive color display
  • Reliable workshop workhorse

Hella Gutmann mega macs 56

  • Made in Germany with reputable software
  • Comprehensive OE-level diagnostics
  • Interactive wiring diagrams and expert tips
  • Full TPMS service functions

Delphi DS-Diagnostika

  • Robust professional tool made for garages
  • Highly detailed diagnostics for thousands of models
  • Labscope, live data, actuation and reprogramming
  • Intuitive software with tech support

Advanced capabilities like live data, component actuations, coding, module programming and full system access justify the investment for commercial use.

Top Professional-Grade Car Fault Code Readers
Top Professional-Grade Car Fault Code Readers
Bosch KTS 590Made in Germany with reputable software
Comprehensive OE-level diagnostics
Delphi DS-DiagnostikaRobust professional tool made for garages
Highly detailed diagnostics for thousands of models
Hella Gutmann mega macs 56Made in Germany with reputable software
Comprehensive OE-level diagnostics
Autel AutoLink AL319Established OBD2 scan tool manufacturer
Quickly scans and erase generic codes
Top Car Fault Code Readers for DIY Use

Tips for Using a Car Fault Code Reader

Follow these tips when using your OBD2 scanner for the first time:

  • Locate the 16-pin OBD2 port, usually under dash near steering column
  • Key on engine but do not start the car before connecting scanner
  • Plug in tool securely and turn on; allow it interface with vehicle
  • Select scan or readout mode and follow menu prompts
  • Carefully note down any codes and freeze frame data
  • Check code meaning via built-in descriptions or online databases
  • Clear codes only after repairs to reset system monitors
  • Disconnect scanner when complete and replace any panels
  • Seek professional help for complex codes or multiple issues

Using a scan tool alongside repair manuals allows DIYers to diagnose and fix many problems themselves. But for continued or manufacturer-specific codes, it’s wise to visit a professional.

Tips For Using A Car Fault Code Reader
Tips for Using a Car Fault Code Reader

Choosing the Best Car Fault Code Reader

With a wide range of OBD2 scanners on the market, how do you select the right one? Here are key factors to consider:

  • Compatibility – Ensure it works with your vehicle’s make, model, and year. Look for wider compatibility across car brands if using for multiple family vehicles.
  • Codes and data – At minimum, it should read and clear general powertrain and emissions codes common across all cars. More advanced scanners read manufacturer-specific codes and display a wealth of sensor data.
  • Live data – The ability to view and graph data like engine rpm in real-time helps pinpoint intermittent faults.
  • Added functions – Extras like battery/alternator tests, immobilizer resets, readiness tests, or Wi-Fi connectivity add convenience.
  • Reliability – Choose a reader from a trusted brand with quality construction that won’t leave you stranded. Also ensure sufficient battery life.
  • Ease of use – Opt for a straightforward interface requiring minimal setup and automatic code searches. Colour displays and connectivity to smartphones improve ease of use.
  • Cost – Inexpensive basic code readers start around £20, while advanced professional-grade scanners run over £100. Know how much capability you really require.
  • Warranty – A longer warranty provides greater peace of mind in case of defects. One year is typically the minimum coverage.


What are the benefits of using a fault code reader?

The main benefits are quickly diagnosing issues to repair them faster, preventing minor problems from becoming major ones, saving money on mechanic diagnostic fees, gaining insight into your vehicle’s health, and being able to clear check engine lights.

Will a code reader work on my car?

Most cars manufactured from 1996 onwards are OBD2 compliant and compatible with code readers. Just ensure the scanner supports your car’s make, model, and year. Some specialize in particular manufacturers.

Where is the OBD2 port located?

Typically under the dashboard on the driver’s side. Check your owner’s manual for the exact location. If not easily accessible, extension cables can bring the port up to your steering wheel area.

What if my check engine light keeps coming back on?

If a code keeps reappearing after clearing it, this indicates the underlying problem has not yet been properly repaired. The scanner allows you to pinpoint the exact issue so mechanics can fix it properly the first time.

Can I use a code reader without mechanic experience?

Yes, they are designed to be easy to use for beginners. Scanners automatically scan and display codes in a straightforward way. Basic internet searches can reveal what each code means for repairs.

Will a basic code reader work or do I need an advanced OBD2 scanner?

Basic readers that show common powertrain and emissions codes are fine for personal use. Professional-grade scanners that access enhanced manufacturer-specific codes are best for mechanics.

What features should I look for in a scanner?

Key features include compatibility with your vehicle, ability to read both generic and enhanced codes, live data streaming, battery tests or other extras, reliability, clear interface, smartphone connectivity, and a reasonable price.

Is it safe to use an OBD2 scanner on my car?

Yes, when used properly according to instructions, code readers safely access computer sensors without risk of damage. Only serious tampering like reprogramming without knowing what you’re doing poses a risk.


Having your own OBD2 fault code reader is invaluable for quickly understanding and addressing engine problems when the check engine light appears. For DIYers, affordable high-quality scanners provide great functionality,

while professional mechanics require advanced tools to support full-service diagnostics. Refer to the recommendations and tips in this guide to select the best car fault code reader and use it effectively when issues arise. With the power to self-diagnose, you can get back on the road faster after problems.

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