DTC P0171 — System Too Lean (Bank 1)
P0171 indicates: System Too Lean (Bank 1).
Diagnostic summary
P0171
What it means
System Too Lean (Bank 1)
Can you drive?
⚠️ Drive with caution
Urgency
Medium 5/10
Typical price
$50 – $600
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Updated May 7, 2026 Seen on Powertrain
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ℹ️ What does it mean?
System Too Lean (Bank 1)
🔍 Symptoms
- • Check Engine Light on
- • Reduced engine performance
- • Increased fuel consumption
- • Unusual engine behavior
⚠️ Possible Causes
- ⚠ Vacuum leak
- ⚠ Faulty MAF sensor
- ⚠ Weak fuel pump
- ⚠ Clogged fuel filter
- ⚠ Intake gasket leak
🚗 Can I drive with this code?
Drive with caution
Drive with caution. Schedule a repair soon.
🔧 How to Diagnose
- 1 Read DTCs with OBD-II scanner
- 2 Check freeze frame data
- 3 Inspect related components
- 4 Clear codes and test drive
🛠️ How to Fix
- 1 Fix vacuum leaks
- 2 Clean or replace MAF sensor
- 3 Check fuel pressure
- 4 Replace fuel filter
💰 Estimated Repair Cost
Repair cost by car / region
Early rough estimate. Accuracy improves as more real repair stories are added.
DIY / parts$18 – $390
Mechanic / labor$23 – $450
Repair range$50 – $600
❓ FAQ
What does P0171 mean?
System Too Lean (Bank 1)
How serious is P0171?
Severity: medium. Drive with caution. Schedule a repair soon.
How much does it cost to fix P0171?
Estimated repair cost: $50–$600 depending on vehicle and region.
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