FAULTBASE
Error CodesASKCars
© 2025 FAULTBASE
All rights reserved.
v2.0.0 • Production
ContactPrivacyImpressum
Home/Cars/Toyota/Corolla/E140 (2006-2013)/how to fix P0174 lean code in my Toyota Corolla E140 (2006-2013)

how to fix P0174 lean code in my Toyota Corolla E140 (2006-2013)

Toyota Corolla E140 (2006-2013)

Error Codes
Severity: mediumDifficulty: mediumError Code: P01742-4 hours
3 min read
550 words

Problem Statement

Learn how to diagnose and fix P0174 lean code in Toyota Corolla E140. Step-by-step guide with diagnostic procedures and repair instructions.

Error Code
P0174
Affected Component
Engine
Estimated Time
2-4 hours

Safety Warnings

  • ⚠Disconnect the battery before working on electrical components.
  • ⚠Allow the engine to cool before opening any components to prevent burns.

Symptoms

  • •Check engine light illuminated
  • •Rough idle or stalling
  • •Decreased engine performance
  • •Poor fuel economy
  • •Increased emissions
  • •Unusual hissing noises from the engine bay

Diagnostic Steps

  1. 1Scan for error codes using an OBD-II scanner to confirm the P0174 code.
  2. 2Inspect the air intake system for any vacuum leaks, including hoses and the intake manifold.
  3. 3Check the Mass Air Flow (MAF) sensor for dirt or damage.
  4. 4Test the fuel pressure with a fuel pressure gauge to ensure adequate fuel delivery.
  5. 5Examine the fuel injectors for clogs or malfunctions.
  6. 6Verify that the engine's fuel trim readings are consistent with a lean condition.

Solution

Solution

1. Preparation

  • Gather necessary tools and parts.
  • Disconnect the battery to prevent electrical shorts.
  • Allow the engine to cool down before working on components.

2. Inspect and Repair Vacuum Leaks

  • Sub-steps:
    1. Visually inspect all vacuum lines and the intake manifold for cracks or disconnections.
    2. Use a smoke machine or carb cleaner to identify leaks; watch for changes in engine RPM.
    3. Replace any damaged hoses or seals.

3. Clean or Replace MAF Sensor

  • Sub-steps:
    1. Locate the MAF sensor, typically found in the air intake duct.
    2. Disconnect the electrical connector and remove the sensor from the duct.
    3. Clean the sensor using MAF cleaner; do not touch the sensor elements directly.
    4. If cleaning doesn’t resolve the issue, replace the MAF sensor with a new one.

4. Check Fuel Delivery

  • Sub-steps:
    1. Connect a fuel pressure gauge to the fuel rail.
    2. Turn the ignition to the "ON" position without starting the engine to check pressure.
    3. The pressure should be within the manufacturer's specifications (typically around 40-50 psi).
    4. If the pressure is low, inspect the fuel pump and filter; replace if necessary.

5. Inspect Fuel Injectors

  • Sub-steps:
    1. Remove the fuel rail from the engine, taking care to relieve fuel pressure first.
    2. Inspect each injector for clogs or leaks.
    3. Clean the injectors with an appropriate cleaner or replace them if damaged.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II scanner
  • •Vacuum gauge
  • •Smoke machine (optional)
  • •Carburetor cleaner or MAF cleaner
  • •Fuel pressure gauge
  • •Socket set

Parts Required

  • •Vacuum hoses (if damaged)
  • •MAF sensor (if necessary)
  • •Fuel pump or filter (if pressure is low)
  • •Fuel injectors (if clogged)

Additional Information

Error Code
P0174
Affected Component
Engine
Estimated Time
2-4 hours
Difficulty
medium
Severity
medium
Tools Required
6 items
Parts Required
4 items

Related Faults

  1. how to diagnose if my Toyota Corolla E140 (2006-2013) has a parasitic drain?

    Learn how to diagnose and fix parasitic drain issues in Toyota Corolla E140 (2006-2013). Step-by-step guide with symptoms, diagnostic steps, and tools required.

    Electrical5 symptoms
  2. how to diagnose P0700 code on my Toyota Corolla E140 (2006-2013)

    Learn how to diagnose and fix P0700 transmission control system fault in Toyota Corolla E140. Step-by-step guide with diagnostic procedures and repair instructions.

    P0700Transmission5 symptoms
  3. why did my Toyota Corolla E140 (2006-2013) battery light come on while driving?

    Learn how to diagnose and fix the battery light issue in Toyota Corolla E140 (2006-2013). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Electrical5 symptoms
  4. how to fix fuel economy issues in Toyota Corolla E140 (2006-2013)?

    Learn how to diagnose and fix fuel economy issues in Toyota Corolla E140 (2006-2013). Step-by-step guide with diagnostic procedures and repair instructions.

    Fuel System6 symptoms
  5. why does my Toyota Corolla E140 (2006-2013) have a rough idle when cold?

    Learn how to diagnose and fix rough idle issues in Toyota Corolla E140 (2006-2013). Step-by-step guide with symptoms, diagnostic steps, and repair instructions.

    Engine6 symptoms
  6. how to reset the tire pressure light on Toyota Corolla E140 (2006-2013)

    Learn how to reset the tire pressure light on a 2006-2013 Toyota Corolla E140. Step-by-step guide with diagnostic procedures and tips for maintenance.

    Electrical4 symptoms

Share this solution

Comments

Sign in to share your thoughts

Sign In

No comments yet

Be the first to share your thoughts

Back to Generation