AutoDiag
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Understand Your Car

What your car reported, how serious it is, and what to do next — in plain language.

Example case — not your car
Stage:Next step ready
Stop drivingNo more questions needed
What to do next
Stop driving when it is safe and arrange recovery or a mobile mechanic.
Why

A flashing engine light or active misfire can quickly damage the exhaust system.

What happens after that

A technician will need to inspect the car before it is driven again.

What we know
  • • P0171: The engine is getting more air than fuel, so it is adding extra fuel to compensate.
  • • P0300: The engine is misfiring — some cylinders are not burning fuel properly.
  • • You reported: warning light
  • • You reported: rough running
What remains unknown
  • • Which part is actually at fault — a code points to a system, not a part.
While you wait
  • • Stay in a safe place away from traffic.
  • • Don't restart the car to test it.
  • • Call emergency services if anyone is hurt or there is fire.
Tell the technician
Vehicle: 2017 Toyota RAV4 [SIMULATED EXAMPLE]
Urgency (safety rules): stop driving
Findings: P0171: The engine is getting more air than fuel, so it is adding extra fuel to compensate.; P0300: The engine is misfiring — some cylinders are not burning fuel properly.; You reported: warning light; You reported: rough running
Not checked / unknown: Which part is actually at fault — a code points to a system, not a part.
Scan: 2/2 systems responded
Stop driving as soon as it is safe and seek assistance

Stop driving as soon as it is safe. Driving further could cause damage or be unsafe. Arrange recovery or a mobile mechanic.

A · Vehicle status

Simulated
2017 Toyota RAV4
Identity entered manually — unverifiedData completeness: high
  • • 2/2 systems responded
  • • 2 stored and 0 pending codes
  • • 3 live readings
  • • 2 reported symptoms

B · What we found

Your car reported 2 fault codes. A code tells us what the car's computer noticed — not which part has failed. The engine is getting more air than fuel, so it is adding extra fuel to compensate.

  • P0171Confirmed by the carFinding certainty: high

    The engine is getting more air than fuel, so it is adding extra fuel to compensate.

  • P0300Confirmed by the carFinding certainty: high

    The engine is misfiring — some cylinders are not burning fuel properly.

A fault code confirms what the car noticed. It does not confirm which part has failed.

C · How serious is it?

Stop drivingStop driving as soon as it is safe and seek assistance

Why: A flashing engine light or active misfire can quickly damage the exhaust system.

Set by fixed safety rules, not AI. An OBD scan alone can never confirm a car is roadworthy.

D · What could be causing it?

Diagnostic confidence: moderate
  1. 1. Vacuum / intake air leakConfidence: moderate
    Supports: P0171 is stored; Long-term fuel trim is +17.2% (engine adding fuel)
    Against / unknown: Not yet tested
  2. 2. Exhaust leak before oxygen sensorConfidence: moderate
    Supports: P0171 is stored; Long-term fuel trim is +17.2% (engine adding fuel)
    Against / unknown: Not yet tested
  3. 3. Worn spark plugs or ignition coilsConfidence: moderate
    Supports: P0300 is stored
    Against / unknown: Not yet tested
  4. 4. Lean mixture or vacuum leakConfidence: moderate
    Supports: P0300 is stored; P0171 (lean mixture) is also present
    Against / unknown: Not yet tested
  5. 5. Dirty or faulty mass airflow sensorConfidence: low
    Supports: P0171 is stored
    Against / unknown: Not yet tested

These are possibilities, not findings. Don't replace a part just because a code mentions it.

E · What should I do next?

Arrange recovery to a workshop

Avoid driving further. Share the mechanic summary below with the recovery service or workshop.

Simple, safe checks you can do
  1. Check the fuel cap is tight
  2. Listen for a hissing sound near the engine with it idling
  3. Note whether the engine light is flashing
Share the summary with a mechanicRe-scan after a short driveAnswer more symptom questions

Something new or different?

Optional. Tap anything you notice — safety advice updates immediately.

F · Your car assistant

No more questions needed — the next step is shown above.

Rule-based decision engine. Language-model explanations are not connected yet.

AI explanation & saving

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G · Share with a mechanic

AutoDiag summary — 2017 Toyota RAV4 [SIMULATED EXAMPLE]
Session: sim-001
Codes: P0171 (stored), P0300 (stored)
Not checked: —
Urgency (rules): Stop driving as soon as it is safe and seek assistance
Suggested checks: Compare short and long term fuel trims at idle and 2,500 rpm; Smoke test intake for leaks; Check MAF readings against expected range; Measure fuel pressure
Possible causes (unconfirmed): Vacuum / intake air leak; Exhaust leak before oxygen sensor; Worn spark plugs or ignition coils; Lean mixture or vacuum leak; Dirty or faulty mass airflow sensor
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