P0174
Medium SeveritySystem Too Lean (Bank 2)
Fuel System
What Does P0174 Mean?
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).
Common Fix
Fix vacuum leak or clean MAF
Estimated Cost (DIY)
$0 - $150
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 Diagnostic Flowchart
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0174.
OEM Manual Evidence
Browse →A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali AWD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali 2WD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-6.0L Service Manual | Operation CHARM Operation CHARM : Car repair...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-5.3L Service Manual | Operation CHARM Operation CHARM : Car repair...
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.
Related Repair Guides
If your vehicle has triggered P0174, these DIY repair guides may help: