Engine-Codes - Toyota - P0171 2003 TOYOTA COROLLA

P0171 2003 TOYOTA COROLLA Code - Air/Fuel Mixture System Lean Bank 1 3ZZ-FE Engine

- Code Popularity: 34,239 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents

|What are the Possible Causes of the P0171 2003 TOYOTA COROLLA Code?

  • Intake air leaks
  • Faulty front heated oxygen sensor
  • Ignition misfiring
  • Faulty fuel injectors
  • Exhaust gas leaks
  • Incorrect fuel pressure
  • Lack of fuel
  • Faulty Mass Air Flow (MAF) sensor
  • Incorrect Positive Crankcase Ventilation (PCV) hose connection

|How to Fix the P0171 2003 TOYOTA COROLLA Code?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|P0171 2003 TOYOTA COROLLA code tech notes

If the P0171 is combined with the P0174 code, it's very likely that the problem is caused by an intake leak. If there are no intake leaks, the next step is to replace the air filter and clean the air flow meter. If the problem persists the front oxygen (O2) sensor may need to be replaced.









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|What is the cost to diagnose the P0171 2003 TOYOTA COROLLA code?

Labor: 1.0

The cost to diagnose the P0171 2003 TOYOTA COROLLA code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

|When is the P0171 2003 TOYOTA COROLLA code detected?

- Fuel injection system does not operate properly.
- The amount of mixture ratio compensation is too small. (The mixture ratio is too lean.)

|What are P0171 2003 TOYOTA COROLLA code possible symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Excessive Fuel Consumption

|What Does the P0171 2003 TOYOTA COROLLA Code Mean?

With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).

Air/Fuel Mixture System Lean Bank 1 3ZZ-FE Engine

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