What causes P0171 on a RAM 1500?

Common causes of P0171 on RAM 1500: Intake manifold plenum gasket leak on 5.7L HEMI V8 causing lean condition on bank 1; PCV valve or hose failure on 5.7L HEMI creating crankcase vacuum leak; MAF sensor contamination from aftermarket oiled air intake on Ram 1500; Exhaust manifold bolt failure causing exhaust leak that reads as lean on O2 sensors; Fuel injector deposits on one or more cylinders reducing fuel delivery on bank 1.

P0171

P0171 RAM 1500

Q: How much does it cost to fix P0171 on a RAM 1500?

Fixes for P0171 on RAM 1500 include: Replace intake manifold plenum gasket with Mopar OE and torque to specification, Replace PCV valve and hoses with Mopar OE parts on 5.7L HEMI, Clean or replace MAF sensor; switch to OE paper air filter if oiled filter was installed, Extract broken exhaust manifold bolts and install ARP studs with new gaskets, Clean fuel injectors with professional service or replace fouled injectors on bank 1.

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

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 RAM 1500 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 RAM 1500.

This repair is rated moderate, meaning some experience and specialty tools required.

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 RAM 1500.

Common Causes on RAM 1500

Intake manifold plenum gasket leak on 5.7L HEMI V8 causing lean condition on bank 1
PCV valve or hose failure on 5.7L HEMI creating crankcase vacuum leak
MAF sensor contamination from aftermarket oiled air intake on Ram 1500
Exhaust manifold bolt failure causing exhaust leak that reads as lean on O2 sensors
Fuel injector deposits on one or more cylinders reducing fuel delivery on bank 1

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

Replace intake manifold plenum gasket with Mopar OE and torque to specification

Replace PCV valve and hoses with Mopar OE parts on 5.7L HEMI

Clean or replace MAF sensor; switch to OE paper air filter if oiled filter was installed

Extract broken exhaust manifold bolts and install ARP studs with new gaskets

Clean fuel injectors with professional service or replace fouled injectors on bank 1

Notes for RAM 1500

The HEMI intake manifold plenum gasket is a known leak point; relatively straightforward to replace.

P0171 RAM 1500

What is P0171?

Common Causes on RAM 1500

Symptoms

Notes for RAM 1500

Check RAM 1500 Specs