P0174
Medium SeveritySystem Too Lean (Bank 2)
Fuel System
P0174 — Instant Answer
System Too Lean (Bank 2)
Severity: MEDIUM SEVERITY
Meaning: Same as P0171 but on bank 2. If both P0171 and P0174 are present, the issue is likely shared (MAF, fuel pump, or large vacuum leak).
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $0 - $150
Most common causes:
- 1. Vacuum leak (35-45% of cases)
- 2. Dirty MAF sensor (35-45% of cases)
- 3. Low fuel pressure (10-25% of cases)
- 4. Intake manifold gasket leak (10-25% of cases)
Common Causes
How to Diagnose P0174
- 1Check for vacuum leaks
- 2Clean MAF sensor
- 3Check fuel pressure
- 4If P0171 also present, focus on shared components
OEM Procedures for P0174
System Too Lean (Bank 2) Found 58 OEM service manual procedures.
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
11 51 000 Removing and installing/replacing the coolant pump (X5 M) - Replacement: Prepare the coolant pump
Showing 8 of 58 procedures
OEM Diagnostic Flowchart
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0174.
OEM Manual Evidence
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Related Symptoms
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Exact Repair Workflows
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Open the exact repair flow most commonly associated with P0174 on this vehicle.
Open the exact repair flow most commonly associated with P0174 on this vehicle.
Related Codes
The engine is running lean on bank 1 — too much air or not enough fuel. The ECM has maxed out its fuel trim trying to compensate. Common causes include vacuum leaks and dirty MAF sensors.
Bank 2 is running rich. If P0172 is also present, look for shared causes like fuel pressure or MAF sensor.
The MAF sensor is reading outside the expected range for current engine conditions. Could be dirty, defective, or have an air leak after the sensor.
Frequently Asked Questions
- Why do I have both P0171 and P0174?
- Both banks lean means a shared component is failing — usually the MAF sensor, fuel pump, or a large vacuum leak affecting both sides.
- Can low fuel pressure cause P0174?
- Yes — a weak fuel pump or clogged filter cannot deliver enough fuel to both banks, causing lean codes on both.
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Author & Review
Written by AllOEMManuals Editorial Team. Reviewed by ASE-certified technicians and updated with factory-reference checks for fitment-sensitive steps.
This guide was drafted with AI assistance and reviewed for accuracy by a human editor.
Last updated: 2026-05-07