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DTC codes

DTC stands for Diagnostic Trouble Code, these are the fault codes your car's OBD2 system generates when something's wrong. FaultNet has a database of these codes that you can search, look up and attach to fault cases.

Looking up a DTC code

  1. Tap Search in the nav
  2. Tap the DTC tab at the top
  3. Search by code (e.g. P0300) or by keyword
  4. Tap a result to see its details

What you see for each code

All users see:

  • The code itself (e.g. P0300)
  • A short description (e.g. "Random/Multiple Cylinder Misfire Detected")

Pro feature

Pro users see the full detail entry for every DTC:

  • Meaning — a plain-English explanation of what the code actually means
  • Symptoms — what the driver typically experiences
  • Causes — the most common root causes
  • Seriousness — how urgent it is to address
  • How to diagnose — step-by-step diagnostic procedure
  • How to fix — common repair approaches

Upgrade to Pro →

Adding a DTC code to a fault case

You can link DTC codes to a fault case when creating or editing it or via the case timeline.

During case creation / editing:

  1. Open the case edit page
  2. Scroll to the DTC codes button
  3. Tap to open the DTC selector
  4. Search for and select the relevant codes

Via the timeline:

When you add a DTC code to a case a "DTC added" timeline entry is automatically created. If you later remove it a "DTC removed" entry is logged too.

Copying a code

Long-press any DTC chip on a case details page to copy the code to your clipboard.

Browsing by category

From the Search page tap Browse to explore DTC codes by category:

  • P codes — Powertrain (engine, transmission)
  • B codes — Body (airbags, doors, windows)
  • C codes — Chassis (ABS, traction control, suspension)
  • U codes — Network / communication

When you add DTC codes to a case they become searchable. Pro users can filter search results to show only cases that include a specific DTC code — very useful for finding others who've had the exact same code on the same car.