Car repair guides: steps, tools and parts | OBDAuto | DVI Reports

How the repair guides work

Choose your car and the job (brake pads, EGR, thermostat, spark plugs, timing): you see difficulty, time, tools, the parts to buy together and the steps, with known pitfalls.

Maintenance and repair guides

• How much does a car service cost and what should it include? — Oil, filters, labour and inspections: published Romanian price examples and how to compare quotes.
• How to read OBD codes: scanners, connection and clearing — Scanners, connection and correct code clearing; live data and freeze-frame explained. Compare ELM327, Bluetooth and professional tools, with official screenshots and…
• When to replace the timing belt or chain: intervals and costs — Find the correct interval, deal with missing history and understand a timing-system quote.
• Bleeding the cooling system and a stuck thermostat: symptoms and procedure — How to recognise air in the circuit or a stuck thermostat (P0128), how to bleed it properly and which signs point to a head gasket.
• Cheap ELM327 scanner: how to use it, which apps are worth it and the risks — Chips, protocols and adapters compared honestly, apps matched to makes and the clear limits of universal OBD diagnostics.
• Dacia Logan II fault codes: symptoms and checks — OBD examples for Dacia Logan II, grouped by engine: misfires, mixture, turbo, EGR and DPF. Explanations and diagnostic checks.
• Dirty or faulty air mass meter (MAF): symptoms, testing and proper cleaning — Which values to check in the scan tool, how to rule out air leaks, how to clean the sensor without destroying it and when to replace it.
• Does cheap engine oil damage your engine? Price, approvals and risks — A low price does not prove poor quality. Learn about specifications, viscosity, provenance and change intervals.
• DPF regeneration guide: warning lights and diagnosis — Understand regeneration, warning lights and when a workshop diagnosis is needed.
• EGR valve cleaning: symptoms, causes and step-by-step procedure — How to confirm with a scan tool that the EGR valve is jammed, how to remove and clean it without damage and which adaptation it needs after refitting.
• Faulty lambda or NOx sensor: symptoms, multimeter test and replacement — The signal a healthy sensor should produce, multimeter testing and why a NOx sensor can only be read with a scan tool.
• Ford Focus III fault codes: symptoms and checks — OBD examples for Ford Focus III, grouped by engine: misfires, mixture, turbo, EGR and DPF. Explanations and diagnostic checks.
• How to clear OBD fault codes and reset the service: steps, readiness monitors and mistakes — When clearing codes is right, what clearing erases, how to check readiness monitors and how to reset the service interval.
• How to force a DPF regeneration: procedure, risks and common mistakes — The conditions the ECU checks before starting regeneration and why driving at higher revs does not fix a loaded filter.
• How to read a VIN: what each character means — Where to find the VIN on the car and in the registration document, the structure of the 17 characters and how to check it has not been altered before buying.
• How to test the battery and alternator with a multimeter: normal values and steps — Resting voltage, cranking drop, charging voltage and parasitic drain, with reference values and the pitfalls of smart charging.
• Injector corrections on a scan tool: normal values, leak-off test and faulty injectors — What positive and negative per-cylinder corrections mean, which conditions matter and how to separate a stuck-open injector from lost compression.
• Live data on an OBD scanner: what it means and how to interpret it — Which parameters matter (temperatures, air mass, fuel trims, oxygen sensors, boost), which values are plausible and how to read them step by step.
• Misfires P0300–P0304: how to test ignition coils and spark plugs step by step — Per-cylinder misfire counters, the coil swap test, spark plug checks and how to rule out the injector and compression.
• Opel Astra K fault codes: symptoms and checks — OBD examples for Opel Astra K, grouped by engine: misfires, mixture, turbo, EGR and DPF. Explanations and diagnostic checks.
• Other maintenance work: brakes, transmission, cooling and costs — What to inspect, when to act and how to budget for brakes, transmission, coolant, battery and air conditioning.
• P0299 and P0234 (turbo limp mode): symptoms, causes and how to fix them — Practical isolation steps: requested versus measured boost, actuator testing with a hand pump and vane checks cold and hot.
• Škoda Octavia III fault codes: symptoms and checks — OBD examples for Škoda Octavia III, grouped by engine: misfires, mixture, turbo, EGR and DPF. Explanations and diagnostic checks.
• Start-Stop battery: how to replace and register it step by step — How battery management works, what happens to an uncoded AGM battery and which procedure each platform requires.
• The Dacia multifunction warning lamp: common causes on Logan, Sandero and Duster — A map of faults behind the zig-zag lamp, from rail pressure and the accelerator pedal to wiring worn by vibration.
• Volkswagen Golf VII fault codes: symptoms and checks — OBD examples for Volkswagen Golf VII, grouped by engine: misfires, mixture, turbo, EGR and DPF. Explanations and diagnostic checks.
• Volkswagen Passat B8 fault codes: symptoms and checks — OBD examples for Volkswagen Passat B8, grouped by engine: misfires, mixture, turbo, EGR and DPF. Explanations and diagnostic checks.
• When to service DSG or ZF automatic transmission fluid — Identify the gearbox, applicable service schedule and quote contents.
• Which scan-tool parameters hint at a used car's real mileage — Where distance is stored outside the cluster, what a generic tool can read and how to use DPF ash without treating it as proof.