Diagnostic Trouble Codes or DTC’s are used to diagnose vehicle issues. For example, when you see that check engine light on your vehicle, these codes are used to decipher them. They are used by mechanics, auto manufacturers, and even at home with aftermarket OBD dongles. DTC’s exist for both light-duty vehicles via the OBDII port and heavy-duty vehicles via a J1939 connection.

Why are DTC’s important? 

Catching a DTC code can help detect a vehicle issue faster so you can identify a problem before it becomes critical. Getting a vehicle off the road when a severe issue exists can help save money and vehicle downtime. 

Identifying these problems can be difficult when running a fleet of vehicles. Automating the process with a telematics solution can help by delivering this information in real-time directly to your computer or mobile device. 

Decoding DTC’s 

Though a code scanner or telematics solution used in your operations will translate and interpret these codes for you, understanding their composition can be helpful in demystifying them. Diagnostic trouble codes consist of one letter and four numbers outlining where the problem exists and what’s wrong with the vehicle.

The code used in the picture below is a great example of why it’s helpful to use a fault code scanner. This issue can trigger the check engine light on your dashboard but when a code scanner is used to diagnose the issue, the most probable cause is due to a loose fuel cap. This can be easily fixed without a trip to the mechanic to diagnose.

What Are Some Common Codes?

While this list is by no means exhaustive, it does include a few ideas of what DTC codes can include:

• P0442: A small leak in the cars evaporative emissions system
• P0401: Exhaust gas recirculation “A” flow insufficient detected
• P0128: Coolant thermostat (coolant temperature below thermostat)
• P0500: Vehicle Speed Sensor Malfunction
  
  

If you are experiencing a vehicle problem, the best way to decode the issue is through the dealer or manufacturer. Some of these codes are specific to the vehicle so where you purchased the vehicle knows the codes best. Another option is to implement a code scanner or telematics solution to detect and diagnose what the issue potentially could be. 

If you are looking for a code scanner,  take a look at our product Raven Connected to see if it fits your needs. Not only can Raven detect and translate DTC codes but the Web App contains Vehicle DTC reports allowing you to look back and see if any DTC’s presented in your vehicles, when, and what they were.

If you are looking for a code scanner take a look at our product Raven Connected to see if it fits your needs.