AI4Car

Knowledge base

Build a diagnostic process, not a parts list

Start with the fundamentals, then use the code library for system-specific checks.

How to read an OBD2 code

A code identifies the system or test that failed; it rarely names the failed part by itself.

  1. 1Save stored, pending, and permanent codes.
  2. 2Record freeze-frame data before clearing anything.
  3. 3Check information for the exact vehicle and engine.
  4. 4Test likely causes in an evidence-led order.

A sensible diagnostic order

Start with context and simple inspections, then move toward circuit and mechanical tests.

  1. 1Confirm the complaint and warning-light behavior.
  2. 2Inspect connectors, hoses, fluids, and obvious damage.
  3. 3Compare scan data with expected conditions.
  4. 4Verify the repair after testing the system.

How to use live data

Compare related parameters at idle, steady speed, and under controlled load.

  1. 1Warm the engine unless the test requires a cold start.
  2. 2Graph related values instead of isolated snapshots.
  3. 3Compare sensor behavior and commanded values.
  4. 4Use model-specific specifications where available.

Put the process into practice

Connect an adapter, read the vehicle's codes, and add context with live data.

Download AI4Car Browse codes