P0170 Fault Code

Fuel Trim Malfunction (Bank 2)

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0170 fault code indicates a fuel trim malfunction in Bank 2. This code may be triggered when the engine control module (ECM) detects that the fuel trim values are outside the expected range. Proper fuel trim adjustments are essential for optimal engine performance and emission control. This issue typically pertains to the air-fuel mixture adjustment for the second bank of cylinders in a V-type engine layout.

What are the symptoms of the P0170 code?

When experiencing a fuel trim malfunction, a vehicle owner might notice:

• Decreased fuel efficiency leading to more frequent trips to the gas station.
• Rough idle or stalling when the engine is running.
• Unusual engine sounds or vibrations.
• Check Engine Light illuminated on the dashboard.
• Possible poor acceleration or lack of power during driving.

What causes the P0170 code?

Several factors can lead to a fuel trim malfunction for Bank 2, including:

• Faulty oxygen sensors providing inaccurate readings.
• Vacuum leaks allowing extra air into the engine, disrupting the air-fuel mixture.
• Fuel injector issues, such as clogging or malfunctions.
• Dirty air filters restricting airflow to the engine.
• Faulty mass airflow sensor (MAF) affecting fuel metering.
• Exhaust leaks that alter the readings of the oxygen sensors.

How to fix P0170?

To resolve the P0170 code, a thorough diagnostic process is necessary:

• Inspect and replace any defective oxygen sensors that may be providing inaccurate data.
• Check for vacuum leaks around hoses and intake manifolds, sealing any found leaks.
• Test fuel injectors for proper operation and clean or replace if necessary.
• Ensure the air filter is clean and replace it if it's clogged.
• Examine the mass airflow sensor and clean or replace it if it’s malfunctioning.
• Look for exhaust leaks which could skew sensor readings.