Error P0172 – how to fix?

Hi!,at this moment. In the following paragraphs you will see a description of fuses and relays Error P0172 – how to fix?

Include with images of block diagrams as well as their locations. Highlighted the cigarette lighter fuse (as the favourite thing people look for).
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Code definition P0172

P0172 is a fault code that is set when the ECU detects that there may be too much gasoline in the engine air / fuel mixture.

Correct air-fuel ratio of approximately 14.7: 1 is essential for maximum engine power and fuel economy.

What does the code P0172 mean

The P0172 code indicates that too much gas has been detected in the exhaust gas leaving the combustion chamber. The ECU uses a variety of instruments such as a Mass Air Flow (MAF) sensor, oxygen sensors and Manifold Absolute Pressure (MAP) to monitor the engine air-fuel ratio.

Most often, the air-fuel ratio is measured by oxygen sensors, which calculate the amount of oxygen and carbon monoxide present in the exhaust gas. The best air-to-fuel ratio known today is 14.7: 1. This particular gear ratio was chosen because it turned out to have the highest power output but the lowest fuel economy.

The ECU has the ability to slightly adjust the air-fuel ratio if it is rich. However, if the compensation margin is too large, code P0172 will likely be set. The term “rich” in this case means that the engine has too much gasoline and not enough oxygen in the air-to-fuel ratio.

What causes the P0172 code?

  • Dirty mass air mass sensor that increases the amount of air entering the engine which can cause an overfuel.
  • Bad oxygen sensor
  • Leaking fuel injector, allowing too much fuel to enter the combustion chamber
  • Faulty fuel regulator that may not regulate the fuel pressure to the engine as it should.
  • Vacuum leak
  • Possible fault in the cooling system, e.g. blocked thermostat or defective coolant temperature sensor
  • Worn spark plugs

What are the symptoms of the P0172 code?

  • The engine warning light comes on
  • Increased fuel consumption
  • Black smoke from the exhaust

How does the mechanic diagnose the P0172 code?

  • Performing a fuel pressure check
  • Using noid lights to check fuel injector pulses
  • Checking the vehicle for vacuum leaks
  • Check mass air flow meter and oxygen sensors
  • Check the air intake system for clogging

The most common errors when diagnosing the P0172 code

The technician may not check the coolant temperature sensor and the cooling system. When the engine is cold, more fuel is added to help warm the engine to the desired temperature. If the coolant temperature sensor is not sending the correct signal, it is possible that the engine ECU assumes it is always cold.

How serious is the P0172 code?

  • The car may not pass the state vehicle inspection because the P0172 code turns on the Check Engine Light.
  • If the air-fuel ratio is rich enough, black smog will come out of the exhaust, which is harmful to the environment.

What repairs can fix the P0172 code?

  1. Repair of vacuum leaks
  2. Replace a damaged fuel injector, fuel pump, or fuel regulator
  3. Replacing the air filter with excessive restrictions
  4. Replace a faulty thermostat or coolant temperature sensor
  5. Replacing spark plugs
  6. Cleaned oxygen sensor and mass air flow sensor.

Additional notes regarding code P0172

It is recommended to check the condition of the spark plugs and the operation of the coolant temperature sensor.

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