Lean code from an air leak (P0171)
- Symptoms
- Rough idle, P0171 code
- Likely cause
- Cracked or loose intake or vacuum hose after the air-flow sensor
- Fix
- Check all hoses and clamps; spray-test or smoke-test for leaks
- Applies to
- SCP10 1SZ-FE
- Related fault codes
- P0171
- Confidence
- low (Q&A)
Sources
Related problems on this car
- Timing chain rattle at idle
- Whistling from the engine bay at idle
- Check-engine light after cleaning the air-flow sensor
- Automatic will not move in D (2 and L work)
Similar problems on other cars
- Intake manifold gasket vacuum leak (1ZZ) · Toyota Corolla (9th gen, E120)
- Throttle body carbon fouling · Toyota Passo (1st gen)
- Ignition coil-on-plug failure / misfire · Toyota Corolla (9th gen, E120)
Where the parts are · Warning lights · Fault codes · Maintenance
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Guidance only – confirm with a mechanic before repairs. All common problems