P0173 – OBD-II DTC

OBD-II DTC P0173 – Fuel Trim too Rich (Bank 1)

DTC P0173 meaning

DTC P0173 indicates that the fuel trim for Bank 1 is too rich. This means that the engine control module (ECM) has detected an excessive amount of fuel in the air-fuel mixture for the cylinders on Bank 1, which can lead to poor engine performance and increased emissions.

DTC P0173 symptoms

Common symptoms associated with DTC P0173 include:

• Decreased fuel efficiency
• Rough idling or stalling
• Black smoke from the exhaust
• Check Engine Light illuminated
• Engine performance issues, such as hesitation or lack of power

DTC P0173 causes

Several factors can contribute to the occurrence of DTC P0173, including:

• Faulty fuel injectors
• Leaking fuel pressure regulator
• Excessive fuel pressure
• Vacuum leaks
• Faulty mass air flow (MAF) sensor
• Defective oxygen sensors
• Improperly functioning engine control module (ECM)

DTC P0173 seriousness

DTC P0173 is considered a serious issue as it can lead to:

• Increased emissions, potentially causing the vehicle to fail emissions tests
• Engine damage due to excessive fuel washing down cylinder walls
• Reduced fuel economy, leading to higher operating costs
• Potential for further engine performance issues if not addressed

How to diagnose DTC P0173

To diagnose DTC P0173, follow these steps:

1. Use an OBD-II scanner to confirm the DTC and check for any related codes.
2. Inspect the fuel system for leaks, including fuel injectors and the fuel pressure regulator.
3. Check the MAF sensor for proper operation and cleanliness.
4. Examine the vacuum lines for any leaks or disconnections.
5. Test the oxygen sensors to ensure they are functioning correctly.
6. Measure the fuel pressure to ensure it is within specifications.
7. Review the ECM for any software updates or faults.

How to fix DTC P0173 step-by-step instructions

To fix DTC P0173, follow these steps:

1. Address any vacuum leaks by replacing damaged hoses or gaskets.
2. Clean or replace the MAF sensor if it is dirty or malfunctioning.
3. Replace faulty fuel injectors or repair any leaks in the fuel system.
4. Replace the fuel pressure regulator if it is leaking or not functioning properly.
5. Test and replace any defective oxygen sensors.
6. Reprogram or replace the ECM if it is determined to be faulty.
7. Clear the DTC using an OBD-II scanner and perform a test drive to ensure the issue is resolved.

How to erase DTC P0173

To erase DTC P0173, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the DTC menu on the scanner.
4. Select the option to clear or erase the codes.
5. Confirm the action and wait for the scanner to complete the process.
6. Disconnect the scanner and start the engine to verify that the code does not return.