Chevrolet-specific code — factory diagnostic data| DTC Data Sheet | |
| Code | P0174 |
| Vehicle | Chevrolet Silverado 1500 (2007-2019) |
| Engine | 4.8L / 5.3L / 6.2L V8 |
| System | FUEL AND AIR METERING |
| Fault type | Performance |
| Official meaning | System Too Lean (Bank 2) |
Definition source: Chevrolet factory description. Diagnostic guidance is based on factory-defined fault logic for this code.
Decode any Chevrolet Silverado 1500 VIN — free recalls, specs & safety ratings — free VIN decoder with NHTSA data
Looking for the cross-vehicle definition? Read the generic P0174 article for the SAE-defined fault logic that applies to all manufacturers.
P0174 Quick Answer
P0174 on a Silverado is the passenger-side equivalent of P0171 — the PCM is adding more than 25% extra fuel to keep mixture stoichiometric on Bank 2 (cylinders 2, 4, 6, 8). If you have BOTH P0171 and P0174, the leak is upstream of the throttle and affects both banks (MAF, PCV, intake manifold). If only P0174, the leak is localized to the passenger side of the intake.
What Does P0174 Mean on a Chevy Silverado 1500?
The Chevrolet Silverado 1500 (2007-2019) stores P0174 when the condition described above is met. This guide focuses on the 4.8L / 5.3L / 6.2L V8 configuration — by far the most common Silverado powertrain. Diagnostic priorities and likely root causes differ from the generic SAE definition because of platform-specific failure patterns documented below.
Symptoms
- Check Engine Light (P0174, often paired with P0171)
- Rough idle that smooths above 1500 RPM
- Hesitation under acceleration
- Slight loss of fuel economy
- Possible P0300 random misfire as lean condition worsens
Common Causes (Most Likely on This Model First)
- Both P0171 + P0174 simultaneously. Affects both banks — look at MAF contamination, PCV system, intake manifold gasket leak (especially the rear corners on Gen-IV LS), or a vacuum leak from the brake booster hose.
- P0174 only (Bank 2 isolated). The leak is localized to the passenger side. Check the passenger-side intake gasket runners and the back of the intake near cylinder 8.
- MAF sensor contamination. A dirty MAF wire under-reports airflow, the PCM injects less fuel, both banks run lean. Clean with CRC MAF-specific cleaner before replacing.
- PCV system fault. The PCV is a controlled leak — if the hose splits or the valve sticks open, the leak is larger than fuel trim can compensate for.
- Leaking injector O-ring on a passenger-bank cylinder. Spray soapy water at the injector base of cylinders 2/4/6/8 with engine running and watch for bubbles.
- Low fuel pressure under load. Returnless GM fuel system should hold ~58 psi key-on and slightly less at WOT. < 50 psi at WOT = suspect fuel pump.
Diagnostic Approach
- Read freeze frame. Note Long Term Fuel Trim Bank 2 (LTFT B2). Anything over +15% is significant. If LTFT B1 is also positive, the leak is upstream of the throttle (MAF, PCV, intake) — affects both banks.
- Smoke-test the intake. Pay attention to the passenger-side gasket at the rear corner (cylinder 8) — common leak point on Gen-IV LS.
- Clean the MAF sensor with CRC MAF-specific cleaner. Drive 50 miles, watch fuel trims.
- Inspect the PCV valve and hose for cracks or stuck-open behavior.
- Spray soapy water at each passenger-bank injector base with engine running — watch for bubbles indicating an O-ring leak.
- Check fuel pressure at WOT — should hold ≥ 55 psi.
Possible Fixes
| Fix | When |
|---|---|
| Clean MAF sensor | Both banks lean — start here, free fix in ~30% of cases |
| Intake manifold gasket set | Smoke escapes from gasket joint |
| PCV valve + hose replacement | Visible crack or sticky valve |
| Injector O-ring replacement (single cylinder) | Bubbles at injector base |
| Fuel pump replacement | Fuel pressure < 50 psi under load |
Can I Still Drive With P0174?
Yes short-term, no long-term. Extended lean operation eventually damages the catalyst and can lean-misfire under load. Fix within a few weeks.
How Serious Is This Code?
Moderate. P0174 alone won’t leave you stranded but the underlying cause typically gets worse, not better.
Repair Costs
| Repair | Cost |
|---|---|
| MAF cleaning (DIY) | $10 |
| MAF sensor replacement | $120 – $260 |
| PCV valve + hose | $45 – $120 |
| Intake manifold gasket set | $420 – $780 |
| Fuel pump replacement | $580 – $950 |
FAQ
What does P0174 mean on a Chevy Silverado?
P0174 means the PCM is adding more than 25% extra fuel to Bank 2 (passenger side) to maintain proper combustion mixture. Combined with P0171 on Bank 1, the cause is usually upstream of the throttle body — MAF, PCV, or intake manifold gasket. P0174 alone points to a passenger-side-specific leak or injector issue.
P0171 and P0174 together on my Silverado — what causes that?
Both-bank lean codes mean the leak is shared between the two banks — meaning it’s upstream of the throttle body. The four most common causes in order: MAF sensor contamination, intake manifold gasket leak at the corners, a cracked PCV hose or stuck-open PCV valve, and (rarely) a vacuum leak at the brake booster line.
How much to fix P0174 on a 5.3L Silverado?
MAF cleaning is $10 and resolves ~30% of cases. MAF replacement: $120-$260. PCV valve: $45-$120. Intake manifold gaskets: $420-$780. Most Silverado P0174 cases resolve in the $10-$300 range.
Will P0174 cause damage if ignored?
Eventually, yes. Extended lean operation overheats the catalytic converter and can cause lean misfires that wash cylinder walls with fuel. You’ll typically see P0420 (catalyst inefficiency) appear after several months of unaddressed P0174.