P0174 on a Nissan: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Drivable short-term, but a lean condition on bank 2 should be diagnosed soon to avoid drivability issues.

What P0174 means on a Nissan

On a Nissan, P0174 means the engine is running lean on bank 2 — the side opposite cylinder 1 — because too much air or too little fuel is getting in. The computer has added as much fuel as it can and still can't balance the mixture. It's the bank 2 version of P0171.

Is P0174 common on Nissans?

P0174 is most common on Nissan V6 models like the Altima, Maxima, Pathfinder, and Murano. Nissan's MAF sensors are known to get dirty or fail with age, which is a leading cause of lean codes on the VQ series V6 engines. Vacuum leaks and intake air leaks are also frequent on higher-mileage Nissans.

Commonly reported on: Altima, Maxima, Pathfinder, Murano.

Symptoms

Check engine light is on
Rough or surging idle
Hesitation or lack of power
Poor fuel economy

Common causes

most common: Dirty or failing mass air flow (MAF) sensor
common: Vacuum leak (cracked hose or intake gasket)
common: Intake air leak after the MAF sensor
less common: Faulty upstream oxygen sensor (bank 2)
less common: Weak fuel pump or clogged fuel filter

How to fix it

Fix	DIY?	Typical cost
Clean the mass air flow sensor with MAF cleaner spray	Yes	$10–20
Inspect and repair vacuum leaks (hoses, gaskets)	Yes	$10–100
Replace the bank 2 upstream oxygen sensor if it's reading wrong	Yes	$60–200
Replace a failing MAF sensor	Yes	$80–250

Frequently asked questions

Why is P0174 common on Nissan V6 engines?

The MAF sensor on Nissan V6 engines gets dirty or fails with age, which makes the computer read the wrong amount of air. A dirty MAF is one of the most common causes of lean codes on Nissans.

What does bank 2 mean on a Nissan?

Bank 2 is the side of the engine that does not contain cylinder 1. Only V6 Nissans like the Altima, Maxima, and Pathfinder have a bank 2.

Can I keep driving my Nissan with P0174?

Short trips are fine, but a lean condition can cause rough idle and hesitation over time. Have it diagnosed soon so a small leak doesn't turn into a bigger repair.