Could vacuum leak (often shared with p0171) cause P0174?

Yes — Vacuum leak (often shared with P0171) is one of the common causes of P0174 (System Too Lean (Bank 2)). A scan-tool freeze-frame and circuit check will confirm whether this is the root cause for your vehicle.

Could dirty or failing mass airflow sensor cause P0174?

Yes — Dirty or failing mass airflow sensor is one of the common causes of P0174 (System Too Lean (Bank 2)). A scan-tool freeze-frame and circuit check will confirm whether this is the root cause for your vehicle.

Could weak fuel pump or low fuel pressure cause P0174?

Yes — Weak fuel pump or low fuel pressure is one of the common causes of P0174 (System Too Lean (Bank 2)). A scan-tool freeze-frame and circuit check will confirm whether this is the root cause for your vehicle.

Could pcv system fault cause P0174?

Yes — PCV system fault is one of the common causes of P0174 (System Too Lean (Bank 2)). A scan-tool freeze-frame and circuit check will confirm whether this is the root cause for your vehicle.

Could failing fuel pressure regulator cause P0174?

Yes — Failing fuel pressure regulator is one of the common causes of P0174 (System Too Lean (Bank 2)). A scan-tool freeze-frame and circuit check will confirm whether this is the root cause for your vehicle.

PowertrainWarning

P0174: System Too Lean (Bank 2)

Same as P0171 but on bank 2. The engine bank with cylinder #2 (typically the side away from cylinder #1) is running too lean. On V6/V8 engines, P0171 + P0174 together usually point to a shared problem like a dirty MAF or a vacuum leak after the throttle body.

Can I keep driving?

Generally safe to keep driving — fix when convenient.

DIY difficulty

moderate

DIY possible with a scan tool and intermediate skills.

Typical cost (Canada)

$200 – $900 CAD

Parts + labor; varies by shop & vehicle.

Common causes

What usually triggers P0174?

1Vacuum leak (often shared with P0171)
2Dirty or failing mass airflow sensor
3Weak fuel pump or low fuel pressure
4PCV system fault
5Failing fuel pressure regulator

Causes are listed roughly in order of how often they're seen on Canadian independent-shop tickets. Always confirm with a scan-tool freeze-frame and a circuit/sensor check before replacing parts.

Related codes

Other P01xx codes

P0100

Mass or Volume Air Flow Circuit Malfunction

P0101

Mass Airflow (MAF) Sensor Range/Performance

P0102

Mass Airflow Sensor Circuit Low Input

P0103

Mass Airflow Sensor Circuit High Input

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