CarFaultIQ

P0174

P0174 — System Too Lean (Bank 2)

Updated By CarFaultIQ Editorial Team

Verify with official recall databases, service records, a mechanic inspection, and local market data before relying on this summary.

At a glance

Quick diagnostic answer

The engine is running lean on bank 2, commonly tied to unmetered air or fuel-delivery issues.

SeverityModerate UrgencyUrgency not yet verified EvidenceSource notes available
OBD code
P0174
System/category
Fuel & Air Metering
Severity
Moderate
Structured severity term
Urgency
Urgency not yet verified
Can I drive?
Drive with caution
Drive with caution and limit trips until it has been inspected; have it checked promptly.
Repair/cost band
$$ · Moderate
Typically a moderate repair; compare a couple of written quotes before authorizing work.
Vehicle applicability
Reported across many makes and models; not specific to one vehicle.
Current applicability note is free text

Computed rule output may be more cautious than stored content and is never used to soften safety-critical risks.

Short answer

P0174 commonly indicates the engine is running lean on bank 2, commonly tied to unmetered air or fuel-delivery issues. Scan the live data and confirm the root cause with a qualified mechanic before replacing parts.

SeverityModerateDrive?Drive with cautionRepairProfessional

Key takeaways

  • P0174 relates to: System Too Lean (Bank 2)
  • Start with the cheapest, most likely checks first.
  • Drive with caution and limit trips until it has been inspected; have it checked promptly.
  • Confirm with live scan data before buying parts.

Can I still drive with this?

Drive with caution

Drive with caution and limit trips until it has been inspected; have it checked promptly.

SeverityModerate

Moderate

Diagnostic flow

  1. What it meansThe engine is running lean on bank 2, commonly tied to unmetered…
  2. Check this firstInspect for intake/vacuum leaks
  3. Likely causeVacuum/intake leak
  4. Can you drive?Drive with caution

P0174 commonly indicates the engine is running lean on bank 2, commonly tied to unmetered air or fuel-delivery issues. Scan the live data and confirm the root cause with a qualified mechanic before replacing parts.

Diagnostic-code summaries are informational — confirm with a scan tool and a qualified mechanic.

Structured DTC reference

What P0174 means

The second bank of cylinders is running lean

A trouble code identifies the circuit or monitored condition that failed its test. It does not, by itself, identify the failed part or prove the same cause on every vehicle.

Cause categories to discriminate

  • Air leak at the inlet manifold

These are structured diagnostic hypotheses, not a parts-replacement list. Vehicle context, symptoms, operating conditions, and test results determine which remain supported.

Severity and drivability

The code alone is not enough to assign one universal severity or “safe to drive” answer. Stop driving for loss of braking or steering, severe overheating, oil-pressure loss, a fuel leak or fire risk, or any rapidly worsening safety symptom.

Add the symptom contextChoose the vehicle

What it means

The engine is running lean on bank 2, commonly tied to unmetered air or fuel-delivery issues.

Common symptoms

  • Check-engine light
  • Hesitation or rough idle

Likely causes

  • Vacuum/intake leak
  • Weak fuel delivery or dirty MAF

Diagnosis steps

  1. Inspect for intake/vacuum leaks
  2. Check fuel trims in live data
  3. Test the MAF and fuel pressure

What a mechanic should check

Confirm the fault with live data and follow code-specific diagnostics before replacing parts.

Vehicle applicability

Reported across many makes and models; not specific to one vehicle.

Repair actions / cost band

$$ · Moderate

Typically a moderate repair; compare a couple of written quotes before authorizing work.

P0174 — vehicles with official records naming this code

P0174 is named in NHTSA-published manufacturer communications or investigations for 53 vehicle families, including:

A code named in a manufacturer communication means the document refers to it for those vehicles. It is not a diagnosis of any car, and it does not mean the code is common on that vehicle.

Frequently asked questions

What does P0174 mean?

The engine is running lean on bank 2, commonly tied to unmetered air or fuel-delivery issues.

Is it safe to drive with P0174?

Drive with caution and limit trips until it has been inspected; have it checked promptly.

What's the cheapest thing to check first?

Inspect for intake/vacuum leaks.

Continue exploring

Related codes

Known faults that trigger this code

Related symptoms

Keep going

Next diagnostic step

Check warning lights Use the dashboard light to decide what to do now. Trace the symptom Match what you can see, hear, smell, or feel. Find vehicle coverage Check model-year problem windows and related faults.

Source & evidence notes

  • Code title: the generic OBD-II definition (SAE J2012) as held in the CarFaultIQ reference tables; not re-checked against the paywalled SAE text.
  • Regulatory context: California Code of Regulations Title 13 section 1968.2 sets on-board diagnostic requirements for fuel system monitoring. It establishes what the vehicle must monitor, not the causes listed on this page. https://www.law.cornell.edu/regulations/california/13-CCR-1968.2
  • Likely causes and checks are CarFaultIQ editorial technical guidance. They have not been independently verified against manufacturer service information.
  • Always confirm specifics with live scan data, the owner manual or service information for your vehicle, and a qualified mechanic before replacing parts.