What causes P0171 on a Nissan Pathfinder?

Common causes of P0171 on Nissan Pathfinder: MAF sensor contamination on QR25DE Rogue or VQ35DE Pathfinder/Murano; Intake manifold gasket leak on QR25DE Rogue from thermal cycling; PCV valve failure causing crankcase pressure imbalance on QR25DE; Cracked intake air tube from engine heat on VQ35DE Pathfinder; Fuel pressure drop from aging fuel pump on high-mileage Murano/Pathfinder.

P0171

P0171 Nissan Pathfinder

Q: How much does it cost to fix P0171 on a Nissan Pathfinder?

Fixes for P0171 on Nissan Pathfinder include: Clean or replace MAF sensor with Hitachi or Denso OE specification sensor, Replace intake manifold gasket on QR25DE and smoke test for remaining leaks, Replace PCV valve and connecting hoses with Nissan OE parts, Replace cracked intake air tube with Nissan OE rubber hose on VQ35DE, Test fuel pump pressure and volume; replace fuel pump assembly if below specification.

System Too Lean (Bank 1) · Powertrain Code · High · Repair: Easy

What is P0171?

The engine is running lean on bank 1 — too much air or not enough fuel. Common causes include vacuum leaks, weak fuel pump, clogged fuel injectors, or a faulty MAF sensor.

When the Nissan Pathfinder triggers code P0171 (system too lean (bank 1)), it typically points to an issue in the powertrain system. This is a high severity code, so address it promptly to avoid further damage or safety concerns. Below you'll find the most common causes, symptoms, and repair options specific to the Nissan Pathfinder.

This repair is rated easy, meaning basic tools, no lift needed.

Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Nissan Pathfinder.

Common Causes on Nissan Pathfinder

MAF sensor contamination on QR25DE Rogue or VQ35DE Pathfinder/Murano
Intake manifold gasket leak on QR25DE Rogue from thermal cycling
PCV valve failure causing crankcase pressure imbalance on QR25DE
Cracked intake air tube from engine heat on VQ35DE Pathfinder
Fuel pressure drop from aging fuel pump on high-mileage Murano/Pathfinder

Symptoms

Rough or unstable idle speed
Hesitation or stumble during acceleration
Engine surging or hunting at idle
Lean misfire under load causing jerking
Poor acceleration response and reduced power
Check engine light illuminated

Recommended Fixes

Clean or replace MAF sensor with Hitachi or Denso OE specification sensor

Replace intake manifold gasket on QR25DE and smoke test for remaining leaks

Replace PCV valve and connecting hoses with Nissan OE parts

Replace cracked intake air tube with Nissan OE rubber hose on VQ35DE

Test fuel pump pressure and volume; replace fuel pump assembly if below specification

Notes for Nissan Pathfinder

MAF sensor cleaning is the most cost-effective first step for P0171 on Nissan SUVs.

P0171 Nissan Pathfinder

What is P0171?

Common Causes on Nissan Pathfinder

Symptoms

Notes for Nissan Pathfinder

Check Nissan Pathfinder Specs