Generic powertrain descriptions
MIT-licensed OBDIICodes, pinned revision a146d4753057, reviewed 2026-09-18. Generic P0/P2 wording; individual entries have not all been independently verified.
Read the MIT notice ↗Signal / vehicle toolsUnderstand the code.
Understand the code.
Then investigate the fault.
Enter a scanner code or search the reference titles. You’ll see where the wording came from and what still needs checking before anyone can name a repair.
01 / Read the definition02 / Keep the scan evidence03 / Test before repair
Look up a code
Works without an account or a recording.
One code is one clue.
Read the exact scanner wording and note which control unit reported it. Pending, stored and permanent codes can describe different stages of the same issue.
Meaning is not cause.
A circuit or performance code may reflect wiring, supply, a sensor, another system or the operating conditions. The vehicle-specific checks decide which.
After the lookup
Useful next checks
These steps preserve the evidence a technician needs, without guessing a part from a code.
- 01
Keep the full scan
Record all codes, the reporting modules, code status and freeze-frame data before clearing anything.
- 02
Add vehicle context
Note the exact make, model, year, engine or powertrain, mileage, warning lights and when the symptom occurs.
- 03
Check the system
Use the maker’s test steps and measured data to separate wiring, controls, mechanical issues and component faults.
Safety first
For a red oil-pressure, brake or overheating warning, or a flashing engine warning with rough running, stop safely and seek assistance. Avoid probing restraint circuits or opening high-pressure fuel systems yourself.
Repair and cost
Get the fault confirmed before pricing a repair.
A code alone cannot produce a credible UK repair quote. Ask for a written estimate after diagnosis, with the proposed work, parts, labour and VAT set out. Check a garage quote → NI Direct explains estimates and quotes ↗
Source notes
What the reference contains
These are openly licensed reference descriptions and a small set of Signal-authored summaries. They are not a live vehicle scan or a manufacturer workshop manual.
Supplemental community titles
CC0 obdex, pinned revision bc58b0eb7273, reviewed 2026-09-18. Wider title coverage, with lower source authority.
Read the CC0 notice ↗Definition authority
SAE J2012 governs diagnostic code definitions and allocations. Its protected code data has not been copied into this lookup. Vehicle-maker and module wording is needed where a generic title is uncertain.