System Too Lean (Bank 2)

What is P0174?

P0174 indicates your engine's Bank 2 is running with too much air and not enough fuel, a condition known as 'lean.' This is a medium-severity powertrain issue that can trigger reduced engine performance and fuel economy. Based on owner reports, it commonly appears in vehicles like the Nissan Maxima and Ford F-150, often related to air intake or fuel delivery problems.

Common Causes

• ●Vacuum leaks or air intake leaks (commonly mentioned with older vehicles like the 2010 Nissan Maxima)
• ●Faulty or dirty mass airflow (MAF) sensor
• ●Clogged or failing fuel injectors on Bank 2
• ●Exhaust leaks (mentioned in owner reports of rusted exhaust systems)
• ●Weak fuel pump or restricted fuel filter

Symptoms You May Notice

• ●Check Engine Light is illuminated
• ●Engine may run rough or misfire (as reported in Honda Accord cases with cylinder misfires)
• ●Reduced engine power or hesitation during acceleration
• ●Poor fuel economy
• ●Engine may occasionally stall at idle

How to Fix It

• ●Diagnose and repair vacuum or intake air leaks ($150-$400, medium difficulty)
• ●Clean or replace the mass airflow (MAF) sensor ($100-$300, easy to medium difficulty)
• ●Replace clogged fuel injectors on Bank 2 ($300-$800, medium difficulty)
• ●Repair or replace leaking exhaust components ($200-$1200, medium to hard difficulty)
• ●Replace fuel pump or fuel filter ($200-$600, medium difficulty)