p0171
Moderate
Chevrolet · Trucks
System Too Lean Bank 1
Quick Answer
Error code P0171 on your Chevrolet Trucks means: System Too Lean Bank 1. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Vacuum leak in intake manifold or hoses
  2. Faulty or dirty mass airflow (MAF) sensor
  3. Weak or failing fuel pump
  4. Clogged fuel injectors
  5. Exhaust leak before the O2 sensor
How to Fix It
1
Inspect intake manifold and vacuum hoses for cracks or loose connections
2
Clean or replace the mass airflow (MAF) sensor
3
Check fuel pressure with a gauge to verify pump output
4
Test and clean fuel injectors using an injector cleaning kit
5
Inspect exhaust manifold for leaks near the upstream O2 sensor
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
MAF sensor cleaner or replacement MAF sensor
Vacuum hoses
Fuel filter
Fuel injector cleaner
Related Error Codes
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