OBD codes / P0171 / Chevrolet Silverado 1500
P0171 on a Chevrolet Silverado 1500
System Too Lean (Bank 1)
5.3L, 4.8L, and 6.2L V8s and the 4.3L V6 (bank 1).
What P0171 usually means on a Silverado 1500
P0171 means bank 1 is running lean, with the PCM adding fuel to compensate for unmetered air or insufficient fuel. On the Silverado the common causes are a dirty mass airflow sensor, vacuum leaks including the PCV system, and on higher-mileage trucks an intake manifold gasket leak. When it appears with its bank-2 twin P0174, the cause is usually shared, like a MAF or PCV problem. Symptoms range from none to a rough idle, a slight stumble, or reduced power.
Most likely causes on this model
- Dirty or failing mass airflow sensor
A contaminated MAF under-reports airflow so the PCM under-fuels, a very common lean-code cause on GM trucks. Cleaning or replacing the MAF often fixes it.
- Vacuum or PCV leak
Cracked PCV hoses and intake leaks admit unmetered air and lean out bank 1, common on aging Silverados.
- Intake manifold gasket leak
As these V8s age, intake gaskets can leak and cause a lean condition, especially on higher-mileage trucks.
- Weak fuel delivery
A tired fuel pump, clogged filter, or dirty injectors can starve the engine enough to log a lean code, particularly under load or towing.
What it costs on a Silverado 1500
Most P0171 fixes on the Silverado are inexpensive: cleaning the MAF or replacing a PCV hose costs little. A smoke test is a modest charge that finds intake and gasket leaks efficiently. Costs only climb if the intake gasket needs replacing or fuel-supply work is required, so confirm the cheap items first.
Fixing it
Read fuel trims and smoke-test the intake before buying parts. Clean or replace the MAF and cure vacuum/PCV leaks first, and consider the intake gasket on higher-mileage trucks if leaks persist.
For the full step-by-step diagnosis order (any vehicle), see the main P0171 guide.
Year, engine and mileage change the answer. Get a diagnosis for your Silverado 1500 — it weighs these causes against your exact configuration and real complaint data.
Diagnose my Silverado 1500 free →Other codes we cover on the Chevrolet Silverado 1500
Related symptoms
Chevrolet Silverado 1500 problems & recalls by year
Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0171 behavior is covered on the main P0171 page. Confirm with a scan tool before buying parts.