Diagolia guides

Reading your diagnostic report

Understand fault code statuses, freeze frame data, the limits of a scan and precautions before clearing codes.

A stationary car’s speedometer with an illuminated yellow stability-control warning light. — A dashboard warning light alone does not tell you a fault code’s status.

Read a report

Active, stored, pending or permanent fault code: how do you read the status?

One code, several statuses. Learn to read the label attached to a fault code without confusing it with severity or a part to replace. The system scanned, diagnostic mode and symptoms matter too.

Read the guide

A person uses a diagnostic tablet connected by a cable inside a vehicle. — Reading data with a diagnostic tool. This photo does not show the fictional record presented in the guide.

Read a report

Freeze frame: how do you read a fault’s recorded data?

Engine speed, vehicle speed, temperature: freeze frame data describes the context of a recorded event. Here is how to read it without drawing conclusions it cannot support.

Read the guide

A mechanic consults a laptop beside a car engine in a workshop. — Diagnosis using a laptop in a workshop. This photo is independent of the guide’s fictional reports.

Read a report

Several fault codes at once: where should you start?

Five codes do not mean five parts to replace. Keep the report, then look for what links the faults or sets them apart.

Read the guide