What are DTC Codes?

If you manage a fleet, staying on top of any engine or other vehicle issues is critical for the safety of your drivers. As it also helps prevent more costly repairs. This is where Diagnostic Trouble Codes (DTC) come in codes that a vehicle’s onboard computer relays about any potential issues.

How do these codes work, and how do you encode them, most importantly, how can you gain remote access to them for your fleet? At fleet pins let’s explore DTC codes and how to interpret them. We’ll also look at how you can manage the maintenance of your fleet with fleet telematics.

What is a DTC Code?

DTC stands for Diagnostic Trouble Codes:

A DTC code is a series of diagnostic trouble codes used by a vehicle’s onboard diagnostics (OBD) system to alert you when a vehicle experiences a malfunction. Different codes have different meanings and represent specific problems in your vehicle.

When the vehicle’s OBD system detects a problem, it generates a specific DTC code and transmits the alert to the vehicle’s instrument panel as a warning light. In vehicles equipped with a telematics system, the alert can be delivered directly to the fleet, you may read “The Impact of Telematics on NEMT Fleet Performance”

The system can also be set up to send the alert directly to the maintenance department. The Society of Automotive Engineers (SAE) created these codes to help vehicles comply with emission regulations.

Types of DTC Codes

Comprehending every DTC code on your vehicle can be challenging because many generic and manufacturer-specific ones could appear.

DTC codes can be categorized into two types:

Type 1: Critical codes

These urgent DTC codes can cause quick and severe damage to the vehicle.

DTC codes such as high engine temperatures and low coolant levels could mean that engine failure is sure to happen. With real-time vehicle diagnostics, fleet managers and technicians can act quickly. They can assess the severity, recommend appropriate action immediately, and locate the nearest service center or garage. This will aid in resolving the issue before it becomes costly and critical.

Type 2: Non-critical codes

While these DTC fault codes do not need urgent solutions, they still require proper attention. This includes emissions-related engine DTCs that don’t lead to excessive pollution. Non-critical codes include those that light up the Malfunction Indicator Lamp (MIL), also known as the Check Engine Light.

What are Common DTCs?

Certain DTCs are more likely to appear than others. Below is a list of common DTCs and their corresponding malfunctions.

• P0442: A minor leak in a vehicle’s evaporative emission control system.
• P0606: A problem with the engine control module (ECM), sometimes called the power train control module (PCM).

• P0101:  A malfunction in the circuit or mass airflow (MAF) sensor.

• P0110: An issue with the circuit of the intake air temperature sensor.

• P0500:  A vehicle speed sensor malfunction.

• P0706: A fault in the sensor circuit range’s transmission range

Disclaimer – It is important to note that while DTCs are useful in identifying a vehicle’s malfunction, they are not a way to decipher why the malfunction occurred. A vehicle needs to be further diagnosed by a mechanic to identify and address the cause of the issue.

How Diagnostic Trouble Codes (DTCs) Work

Whenever your vehicle experiences a problem or detects a fault, its OBD system generates a DTC code. Once detected, the OBD system will alert you by displaying the DTC code in visible warnings, such as an illuminated check engine light. A DTC code lets external devices, such as an onboard diagnostics scanner (code reader), interact with your vehicle’s OBD system. For more information read the blog “What is the OBD-11 port”.

Initially, several versions of onboard diagnostics interfaces largely varied depending on the vehicle manufacturer. But today, there are two main standards used to read DTC codes:

OBD-II: OBD-II codes are used in light (6,000 to 10,000 lbs) and medium-duty vehicles (10,001 to 26,000 lbs). In US, all vehicles that were built and sold after January 1st, 1996 are required to follow this standard.

J1939: J1939 codes are used in heavy-duty vehicles (26,001 to over 33,000 lbs) like city transit buses, refuse trucks, and cement trucks.

When a vehicle’s check engine light turns on, a technician can plug a handheld OBD scanner into its diagnostic port (typically under the dashboard below the steering wheel column). Once connected, the scanner will display an error code.

Using an OBD scanner requires direct access to the vehicle in question. However, with the right telematics system, a fleet manager can receive real-time alerts anytime a vehicle generates a DTC code.

How Do DTC Codes Help with Fleet Management?

Let’s say you have an outdated fleet telematics system that isn’t set up to deliver you the daily data your vehicles produce. If such is the case, you may have to depend on your drivers or field service technicians to notify your offices of DTC codes when they notice these warnings on the control panels of their vehicles.

Alternatively, you may need to assign someone to physically check each vehicle regularly to ensure that all systems are functioning properly, as indicated by the instrument panels. These two procedures are not as effective as they could be.

A fleet-wide vehicle tracking system could gather and send this information to your business, enabling you to respond to DTC codes in your vehicles far faster and more reliably. The right GPS tracking software by fleet pins may help you increase your vehicles’ overall return on investment (ROI), decrease vehicle downtime, and maintain more dependable and effective fleet operations for your company and your fleet.

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It can also provide real-time problem codes to your fleet management team so for more information Book A Demo now.

Conclusion

DTC codes are used to diagnose malfunctions in a vehicle. Sometimes, they can be minor, like a loose fuel cap, or more serious, like a faulty oxygen sensor. If your vehicle triggers an engine fault code, it’s important that you know what the DTC code means. Handheld scanners can help you quickly identify the problem. However, if you manage a fleet of vehicles, using a telematics system like Track obit offers a better way to monitor diagnostic codes.

If you manage a fleet, staying on top of any engine or other vehicle issues is critical for the safety of your drivers. As it also helps prevent more costly repairs. This is where Diagnostic Trouble Codes (DTC) come in codes that a vehicle’s onboard computer relays about any potential issues. How do these codes work, and how do you encode them, most importantly, how can you gain remote access to them for your fleet? At fleet pins let’s explore DTC codes and how to interpret them. We’ll also look at how you can manage the maintenance of your fleet with fleet telematics.