P0173 - OBD Trouble Code

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The fault code P0173 can be described as fuel trim malfunction bank 2. This would mean that the powertrain control module which is also known as engine control module has detected a fuel trim outside the specified range set by the manufacturer of the vehicle. This code is generally detected when the fuel injection system is not operating properly or there can be an incorrect level of mixture ratio being compensated. The fuel trim can be positive or negative.

The powertrain control module would receive the signals from the oxygen sensors and it would adjust the amount of fuel, allowing the engine to receive based on the readings provides by the oxygen sensors. If there is signal coming from the oxygen sensor then it would mean that the engine would need less fuel, and the powertrain control module would act accordingly through a negative trim. If the O2 sensor is saying that it requires more fuel, then the powertrain control module would carry out a positive trim.

This code can start triggering by the engine control module when it would detect that the air fuel ratio is too lean or too rich. For a lot of lean and rich conditions, the engine control module can start compensating for the lack or gas entering the engine. But if the compensation would be too much, then P0173 fault code can set up.

What causes this problem with the Fuel Trim Malfunction (Bank 2)?

• The mass air flow sensor can be dirty or can have some faults
• There can be a leakage in the intake manifold or torn intake boot
• Issue of leakage in the vacuum
• The fuel injector might appear to be faulty
• There can be some defects in the fuel pressure regulator
• Pinched fuel line

1. Engine Control Module - A faulty Engine Control Module can cause a lot of issues. It would be nice if you get it replaced on time.
2. Mass Air Flow Sensor - The P0173 code can also arise due to some issues in Mass Air Flow Sensor. So, it is advised to replace them as soon as possible.
3. Fuel Injector - Do you remember when was the last time you got your car Fuel Injector checked up? A damaged Fuel Injector can cause a lot of issues like displaying P0173 code.
4. Fuel Pressure Regulator - Fuel Pressure Regulator is an important car part which should never be neglected. May be there is some fault in it due to which P0173 code may start flashing.
5. Intake Manifold - Is your Intake Manifold damaged or broken? Don’t worry as we have solutions for all your problems.

Our main motive is to achieve customer satisfaction and that’s why we will help you to diagnose P0173 code by mentioning some major symptoms below:

Common Symptoms

• There can be an illumination in the check engine light
• An increase in the amount of smog or soot from the exhaust
• Loss in acceleration
• Hesitation or misfire during idle
• The overall fuel consumption might start increasing

Have a look at some ways with which you can correct the P0173 code:

• Replacing the mass air flow sensor
• Replacing the fuel pressure regulator
• Replacing the intake manifold gaskets
• Repairing or replacing the engine air filter intake system
• Replacing a vacuum line connected to the throttle body
• Repairing a leaking brake booster
• Replacing a damaged fuel line
• Replacing a faulty fuel injector

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• Make sure that you visually inspect the mass air flow sensor
• The resistance of the mass air flow sensor should be tested and circuitry with a digital multimeter
• A fuel pressure test should be performed
• Carefully inspect the wiring of the fuel injectors for fraying
• You must check the intake manifold and vacuum lines for leakage
• A scan tool can be used to specify the fuel trim out of range (short-term or long-term)

Common Mistakes When Diagnosing The P0173 Code

• One common mistake can be replacing the mass air flow sensor without cleaning or testing it first
• Declaring a car part defective without checking for more common causes, such as vacuum leaks
• You must use a scan tool to determine if there is an issue with either the short- or long-term fuel trim
• Failure in inspecting the wiring of the component thought to be at fault

P0170 - Fuel Trim Malfunction (Bank 1)