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Top 10 Things You Must Know About DTC Codes – Matrack Insight

If you’re in charge of a fleet, the fear of vehicles breaking down mid-route is enough to keep you up at night. The consequences would be disastrous, disrupting your delivery schedule and incurring hefty repair costs. But what if there was a solution that could turn this nightmare into a dream? Imagine having a system that constantly monitors your vehicles’ engine performance and alerts you to potential technical issues. With such a proactive tool, you could take prompt action to address problems before they become major concerns.

Enter Diagnostic Trouble Codes (DTC). These codes provide remote access to information about your vehicle’s problems and guide you on how to maintain smooth and safe operations. In this article, we’ll delve into the world of DTC, explaining how they work and how effectively they can help you manage your fleet’s maintenance for optimal performance. So, buckle up and get ready to learn!

What are DTC Codes?

DTC, short for Diagnostic Trouble Codes, is a series of codes generated by a vehicle’s onboard diagnostics (OBD) system to indicate any detected technical faults in the truck. Through self-diagnosis, the vehicle’s electronic system identifies issues that require attention and assigns a specific code to each problem. This code is displayed as a warning light on the instrument panel, alerting the driver. 

DTC codes

Additionally, you have the option to set up an alert system that delivers notifications directly to your computer or the maintenance department, ensuring timely awareness of any potential issues in your fleet vehicles.  

How DTC Codes Help Managing Fleet Operations?

Diagnostic Trouble Codes (DTC) are predictive indications of any technical issues arising in the vehicle that might lead to further problems. Some faults may need an immediate resolution to avoid sudden breakdowns and repairs. These codes provide regular updates on vehicle performance and any abnormalities detected based on engine diagnostics. 

Above all, these data on vehicle performance guide you to take necessary proactive measures to improve the automobile’s condition, performance, and overall cost-efficiency. You can achieve several benefits by getting timely information through DTC codes, including lower maintenance costs, reduced breakdowns, improved fuel economy, and better CSA scores.

The primary benefits are as follows:

Maintenance Management

Regular vehicle performance tracking and automated engine diagnostics provide data for analyzing vehicle health and maintenance. The system detects technical issues and notifies you via DTC, enabling proactive maintenance and repairs to enhance efficiency and prevent breakdowns. Maintenance records guide staff in identifying and resolving potential faults.

Improved Efficiency

A well-maintained vehicle is vital for productivity and efficiency. Stay informed about your vehicle’s issues through diagnostic trouble codes (DTCs) for preventive measures and maintenance. This boosts performance, reduces breakdowns, and downtime.

Regularly tracking engine data allows better maintenance management. In case of a major problem, quick plans can replace the vehicle to meet service commitments.

Cost Control

An efficient fleet operation improves cost-efficiency. DTC codes help focus on areas for better vehicle performance. Maintain your vehicle for fuel efficiency and cost reduction. Avoid major repairs, saving money. Fewer faults mean quicker trips, more consignments, and increased revenue. Lower operational costs improve profit margins in a competitive market.

Better Customer Service

Assure timely delivery by monitoring and correcting truck issues with DTC codes, ensuring smooth operations and on-time service. Improved dependability and customer service enhance your reputation, allowing you to handle more consumers and gain a competitive edge with cost savings.

Reduced Insurance Premiums 

Understanding the DTC codes helps you resolve technical issues, maintain vehicle health, and minimize failures, damages, and repairs. Insurance companies reward proactive measures to reduce faults and accidents, leading to lower premiums. By using a monitoring and alert system for maintenance, you can cut insurance expenses significantly.

Educate Drivers to Address Faults

Receive fault codes and definitions to address immediate issues. Alert drivers to avoid vehicle damage. Inform them to contact a mechanic or service station. The Telematics system sends DTC codes and descriptions to your computer. Instruct drivers on resolving the problems. Quick action prevents serious downtime and ensures the best outcome.

Types of DTC Codes

The OBD system can detect a variety of problems in a car, some of which require quick attention owing to their severity. It can be useful to categorize these error codes based on their severity. Here’s a breakdown of the two categories:

AspectCritical DTC CodesNon-critical DTC Codes
MeaningIndicate faults that may cause immediate and severe vehicle damage.Refer to situations that do not demand immediate care, but still require attention.
ExamplesHigh engine temperatures, low coolant levels, risk of engine failure, etc.Emission-related engine problems, excessive pollution, etc.
Response TimeImmediate action is critical; contact local service facility promptly.Timely attention is necessary to maintain environmental standards and vehicle performance.
Risk AssessmentSignifies urgent issues that can lead to costly and urgent problems if ignored.Can lead to environmental harm or gradual deterioration of vehicle performance if not addressed.
Potential ConsequencesSevere vehicle damage or failure, safety risks.Environmental pollution, decreased performance over time.
Recommended ActionsAct quickly, seek professional service immediately.Address the issue in a timely manner, schedule maintenance as soon as possible.

Remember that both critical and non-critical DTC codes are important in diagnosing and maintaining the health of a vehicle. Ignoring any DTC code, no matter how minor, might lead to more serious problems in the future. To ensure the vehicle functions effectively and safely, call a competent mechanic or service facility to properly diagnose and handle the DTC codes.

Structure of DTC codes

A DTC code comprises five characters, each holding valuable information about your vehicle’s condition. With an advanced fleet management solution, you’ll receive the meaning of each code automatically. Standard coding protocols aid in identifying the specific area of your vehicle that needs inspection. Let’s explore the code structure and standard abbreviations.

The First Character

The DTC codes start with a letter that denotes the part of the vehicle that has a fault.

  • P codes: These indicate a problem related to the powertrain, such as the engine, transmission, and fuel system problems.  
  • C codes: It indicates the chassis-related problem. It mainly refers to mechanical systems outside the passenger compartment, such as steering, suspension, and braking. 
  • B codes: This code indicates that the problem relates to the body of the vehicle, which means the parts found in the passenger compartment area.
  • U codes: It corresponds to a problem with the vehicle’s onboard computers and integration functions that the OBD manages.

 The Second Character 

A second character is a number, either 0 or 1.

  • 0: It is a number that denotes your vehicles are following the OBD-II international standard.
  • 1: It represents the code related to a specific vehicle make or model. When you see this number in the code, you need to contact the vehicle manufacturer directly for further information and action. 

The Third Character

If the second character of the DTC code is a “0,” then the third character helps you determine which subsystems of that particular area are malfunctioning. There are eight numbers as follows:

For example, if the code indicates powertrain faults, this number will tell you the exact vehicle subsystem that experiences the trouble.

  • 0 – Fuel and air metering and auxiliary emission controls
  • 1 – Fuel and air metering
  • 2 – Fuel and air metering – injector circuit
  • 3 – Ignition systems or misfires
  • 4 – Auxiliary emission controls
  • 5 – Vehicle speed control, idle control systems, and auxiliary inputs
  • 6 – Computer and output circuit
  • 7 – Transmission 

The Fourth and Fifth Character 

The last two characters of a DTC code are a number that defines the exact problem that your vehicle is experiencing. It can be any number between zero and 99.

The best source for explaining DTC is the dealer that sold or leased you the truck or the manufacturer of that model. Some DTCs are specific to the vehicle. You can download the complete list to your device and access it any time, or consider implementing a vehicle diagnostics software solution that provides definitions for you.

For example, code P0442 indicates a small leak in the evaporative emission system.

Common DTC Code List

The technical issues can vary depending on the condition or maintenance trends. There are some problems that most fleets encounter. These faults, along with their DTC, are given as follows:

Code Fault
P0101 Mass Air Flow (MAF) circuit or sensor fault
P0110 Malfunction of intake air temperature sensor circuit
P0442 A small system leak within the evaporative emission control system
P0500 Malfunction in the speed sensor
P0606 A PCM (or ECM) powertrain malfunction
P0706 A transmission range sensor circuit range fault 

How to Read and Interpret the DTC Codes?

You need a tool to check and read the faults and provide the information. You can use a code reader or scan tools that identify technical issues and generate data as a five-character code or one-liner. But,  can one tell what the code indicates?

It is more than just accessing the DTC codes. You need to know how to decode or interpret those codes and get the definition for each fault code so that you can take action accordingly. 

A standard DTC list or database is available on different websites that can help you out. Your vehicle manufacturer can provide a detailed interpretation of codes and relevant reference material according to the specific model of the vehicle.

You need a diagnostic connector to read the DTC codes. The latest vehicle models generally have the required connectors. Although, there can be some variations in the software and hardware depending on the make, model, and year. If your vehicle model is before 1996, you will require specific adapters.

In the truck, you need to plug the scanner into the 16-pin OBD-II diagnostic connector, usually located on the left side of the steering and under the dashboard. The following steps will guide you to read DTC fault codes using a scan tool.

  • Initially, find the location of the 16-pin connector in the vehicle. Some connectors are fixed in the center console, while in other cars, you may find them on different types of panels. If you are still looking for the OBD-II diagnostic connector, consult the vehicle manual provided by the manufacturer.
  • Plug your code reader or scanner in the diagnostic port and turn on the ignition or keep the engine running. It allows the scan tool to communicate with your vehicle’s engine.
  • You will find an option in the menu to read codes. The scan tool may ask for specific information, such as the vehicle model and year, so you can set it right to get the data automatically.
  • The scan tool will start analyzing the diagnostic faults and shows the trouble codes, usually in numerical order.  

You can transfer the codes to a smartphone or computer via Wi-Fi, USB, or Bluetooth, using advanced features of the scan tools. It helps you to thoroughly check and analyze the nature of the problem your vehicle is experiencing. You can then consult the manufacturer’s website or other sources for a detailed interpretation of these diagnostic trouble codes.

Fleet Management Solutions for DTC codes

By going beyond OBD-II or DTC scanners, you can acquire more efficient engine diagnostic capabilities. Modern telematics systems can monitor real-time engine and system performance and send out rapid alerts if any problems are discovered. Robust fleet management systems with dependable tracking technology can detect defects automatically and convey information to fleet managers, employees, and drivers, allowing for swift decision-making. 

Telematics systems collect data on vehicle speed, fuel usage, engine condition, and other performance factors, which can be monitored via a software interface in addition to trouble codes. For seamless monitoring and increased efficiency, advanced fleet management systems deliver problem codes and definitions at the same time. 

Advantages of DTC Fleet Telematics Solutions

DTC Fleet Telematics Solutions like Matrack play a crucial role in providing real-time information about a fleet’s vehicles, their performance, and potential technical issues. By connecting to a vehicle’s diagnostic port, these solutions generate fault codes and offer valuable insights into the vehicle’s health and maintenance needs. Here are the advantages of using Fleet Telematics Solutions:

1. Real-time Access to Fault Codes

– Connects to the truck’s diagnostic port and generates fault codes in real-time.

– Enables fleet managers to access these codes promptly, providing immediate insights into any technical issues.

2. Proactive Issue Resolution

– Alerts fleet managers whenever potential faults or technical issues are detected in the vehicles.

– Allows fleet owners to address problems before they escalate, ensuring timely maintenance and reducing breakdowns.

3. Enhanced Maintenance Awareness

– Provides fleet managers with comprehensive information on maintenance needs that require immediate attention.

– Helps prevent critical problems and breakdowns by facilitating predictive maintenance planning.

4. Improved Fleet Performance

– Allows continuous monitoring of engine performance and the smooth functionality of vehicle parts.

– Enables proactive measures to ensure trouble-free and efficient performance of the fleet.

5. Timely Scheduled Maintenance

– Informs fleet managers about scheduled maintenance requirements, ensuring that services are carried out promptly.

– Optimizes the lifespan of the vehicles and reduces premature wear and tear.

6. Reduced Reliance on Drivers

– Eliminates the need to rely solely on drivers for information about fault codes and technical issues.

– Minimizes the risk of miscommunication and ensures accurate data for mechanics and repair personnel.

7. Efficient Fleet Management

– Enables better fleet management by providing comprehensive insights into the health of individual vehicles.

– Facilitates data-driven decision-making to improve overall fleet performance and cost-effectiveness.

With these solutions, fleet owners can significantly enhance their maintenance practices, reduce downtime, and optimize the performance and longevity of their trucks, leading to increased operational efficiency and cost savings.

Matrack Solutions 

Today, we handle advanced technology in almost every aspect of business operations. When it comes to vehicle maintenance and addressing faults, you need to be very specific about the nature of troubles or technical issues so that you can rectify them within the optimum cost and time.

Matrack offers onboard diagnostics and tracking solutions to help you catch maintenance issues early and accurately and resolve those with quick actions. The Matrack fault detection system helps you with the following features:

  • Monitor and generate fault codes through a direct connection to onboard vehicle diagnostics
  • Diagnose vehicle problems in real-time and as they likely to occur 
  • Monitor speed, idle time, fuel efficiency, and service schedules
  • Analyze and calculate trends to find out what parts wear out faster than others
  • Highlight important issues that are frequent and need appropriate actions


Your fleet operations become more efficient and trouble-free as you regularly keep your vehicles running well by taking care of maintenance needs.

DTC codes inform you about technical issues in vehicles as they arise and let you take prompt and proactive actions to improve reliability, safety, and cost-effectiveness in fleet operations.

This article gives a thorough overview of DTC, its format, and access and decoding procedures to help you get the maximum benefits.