P0171 (blink 25) on Toyota Passo (KGC10): Fuel Trim System Too Lean (Air-Fuel Ratio Lean Malfunction,
Short answer: P0171 means “Fuel Trim System Too Lean (Air-Fuel Ratio Lean Malfunction,”. The car’s computer has found a fault in the Engine control (EFI) system and turns on the Check engine light (MIL). First check: is the fuel pressure normal?.
- Code
- P0171 · blink 25
- System
- Engine control (EFI)
- Dashboard light
- Check engine light (MIL)
- Also sold as
- Daihatsu Boon, Daihatsu Sirion (M300)
- Applies to
- 1KR-FE: M300 (Sirion export = JDM Boon M300S/M301S(4WD? see gaps) & Passo KGC10/KGC15). JDM-spec ECU not separately documented | K3-VE: M301 (Sirion 1.3 = JDM Boon M310S? / Passo QNC10)
- Confidence
- high (factory manual, export spec)
- Source
- carmanualsclub.com
Likely causes
- Open wire or short circuit in the oxygen sensor circuit
- Oxygen sensor
- Engine coolant temperature sensor sensor
- Evaporative emission purge VSV
- EFI ECU
What to check, in order
- Is the fuel pressure normal?
- Is the injector normal?
- Is the oxygen sensor normal? Confirmation driving pattern (For EU specifications) Vehicle speed e 70 km/h w Idling IG SW OFF Time Warmed up C13E5564ES10
Related on this car
- Stalling at idle with A/C + brake, hard start
- All fault codes for this car
- Warning lights
- Where the parts are (parts map)
- Common problems
Same code on other cars
- P0171 · Toyota Vitz (1st gen)
- P0171 · Toyota Corolla (9th gen, E120)
- P0171 · Toyota Corolla (11th gen, E170)
- P0171 · Toyota Corolla (10th gen, E140)
- P0171 · Honda City (5th gen, GM2)
- P0171 · Honda Civic (10th gen, FC)
- P0171 · Suzuki Wagon R (Pakistan, K10B)
- P0171 on all cars compared
Clearing the code does not fix the fault. If it comes back, the problem is still there. For brakes, airbags and steering, see a trained mechanic.