DTC guidance: from fault code to evidence
Understand what DTCs indicate, review code status and freeze-frame data, and confirm diagnostic hypotheses with vehicle-specific measurements.
ContactA code describes a detected condition
A DTC is recorded when a control module detects conditions that meet its monitoring criteria. Its description alone does not identify a failed part. Supply, wiring, connections and other operating conditions may contribute to the same finding.
Preserve context before clearing
Record the reporting module, the exact scan-tool description and code status. Save freeze-frame and relevant data before clearing, following the manufacturer procedure. Status terminology can vary between systems and tools.
Relate codes to the complaint
Consider whether codes occurred together and whether they match the complaint. An underboost indication, for example, calls for comparison of requested and actual pressure, load conditions and manufacturer-prescribed checks. The indication alone is not a reason to replace the turbocharger.
Use DiagVima to organise the evidence
DiagVima helps organise case details, possible causes and checks. Selecting and interpreting a measurement depends on the vehicle, engine, ECU and official procedure. Confirm the hypothesis with evidence and verify the result after repair.