Have you read P0171 or P0174?
Discover what fuel trims tell you and which comparisons can make the reading useful.
SCA Driver Observatory
Problems reported.
Evidence kept distinct.
1,110,582 unverified real reports, 9 documented cases and 3 simulations in a separate section. No confirmed cause or repair is declared.
A report is a starting point
The accounts come from a public archive, not an SCA mechanical inspection. Symptoms and DTCs may be incomplete or misinterpreted; no fault frequency is inferred from counts. We preserve provenance without republishing personal data or confidential procedures.
Start with what you have actually noticed
OBD2 is a diagnostic system found in compatible cars. Control units, the onboard computers that manage vehicle systems, make some fault codes and operating data available. An OBD2 app lets you read this information through a compatible adapter.
You do not need an app, adapter or code to start exploring here. Note the warning light or symptom and when it appears, then look for relevant reports. A similar experience does not prove that your car has the same fault. For safety and urgency, follow your vehicle handbook and seek professional help when needed.
Editorial examples, not real testimonies or confirmed diagnoses.
Keep the evidence separate
- Real reports: someone described an observation; the cause may be unconfirmed.
- Documented or verified information: read the evidence and its scope. A documented case is not automatically a confirmed diagnosis.
- Synthetic examples: artificial scenarios shown separately. They are not driver testimonies.
- Hypotheses and unclassified data remain uncertain. Even a source-backed explanation is not a diagnosis of your vehicle.
Understand your car's data
A trouble code is a starting point. These guides help you read available information, preserve context and ask more precise questions of whoever will inspect the vehicle.
Four documentary guides with illustrative examples. A final technical review has not yet been completed.
Is the engine running unevenly with P0300 or P0301?
Distinguish the cylinder report from the cause and prepare useful information for the check.
Does the OBD temperature seem impossible? (IT)
Check which temperature you are viewing and why an extreme number requires context.
Does a fault remain after repair, or is the warning light off? (IT)
Understand code states, freeze frames and monitors before clearing useful information.
Search real reports and cases
The symptom filter uses themes automatically recognised in the account: it does not confirm the symptom. Mentioned DTCs are not automatically instrument readings. The index is divided into static groups, loaded as needed; no dynamic database.
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Documented case
SsangYong Rodius 2016 — documented OBD observation
Documented case
Peugeot 308 2015 — documented OBD observation
Documented case
Peugeot Expert 2014 — documented OBD observation
Documented case
Chevrolet Captiva 2011 — documented OBD observation
Documented case
Kia Sportage 2017 — documented OBD observation
Documented case
Citroën Berlingo 2014 — documented OBD observation
Documented case
Peugeot 2008 2022 — documented OBD observation
Documented case
Ford Fiesta 2013 — documented OBD observation
Documented case
Toyota Yaris XP90 — MAF and lean-mixture reports
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Browse all makes and groups, even without JavaScript →
Simulations: a separate collection
The 3 artificial examples are not mixed with real accounts.
Open synthetic examples →How to read the qualifications
Unverified real report
Complaint attributable to a real source; no confirmation of the diagnosis.
Documented case
Observation accompanied by documentation or additional acquisitions; not equivalent to a demonstrated cause.
Verified case
Requires evidence of the cause or intervention. No available record currently meets this status.
Synthetic example — simulation
Artificial scenario, presented only as a simulation and separate from real cases.
Provenance and data protection
NHTSA complaints: public data acquired on 6 October 2026; the registry is American, and the country of each event is not inferred. Cases with the same vehicle and ODI number are combined. Full accounts, locations, VINs, contacts and personal data are excluded from the export. Keywords are not diagnoses. DieselOBD and community observations retain their source and licence in the entries.
NHTSA terms · OBD2 code catalogue (IT) · Diagnostics with Smart Control OBD2
Privacy reports and corrections
Sources, minimisation and removal requests. Provide only the URL and case reference; do not send other unnecessary personal data.
What to observe before drawing conclusions
Keep the exact code and any status shown, the symptoms, and the circumstances in which they appeared. If live readings are available, note their names, values and units. Missing information is not zero and a reading does not by itself confirm a cause.
Use the existing guide to keep the context
Smart Control OBD2 reads available codes and parameters through a compatible adapter. It helps you observe and retain context; it does not automatically identify the cause of a fault. Coverage depends on the vehicle, control unit and adapter.
OBD2, PRO or Premium? Choose your app and check existing rights