P0174 on the 2022 Acura Integra: What It Means
The 2022 Acura Integra returned as a compact sport sedan powered by a 1.5L turbocharged four-cylinder engine (L15CA) producing 200 horsepower and 192 lb-ft of torque, shared with the Honda Civic Si. Since this is an inline-four engine, P0174 (System Too Lean Bank 2) on the Integra indicates a generalized lean condition rather than a bank-specific issue. The PCM has detected that long-term fuel trims have exceeded the acceptable range as it tries to add fuel to compensate for excess air in the system.
Symptoms You Will Experience
- Check engine light on the dashboard
- Rough or slightly surging idle
- Hesitation during light acceleration
- Reduced turbo boost sensation
- Slightly worse fuel economy than the typical 30+ MPG
Top Causes of P0174 on the Integra
1. Boost Leaks
The L15CA turbo engine uses a single turbocharger with an air-to-air intercooler and charge piping. Common boost leak points include the intercooler end tank connections, the charge pipe-to-throttle body coupling, and the bypass valve. Even on a new Integra, a factory clamp that was not fully tightened or a coupler that slipped during shipping can create a leak. A boost leak test using 15 psi of regulated compressed air through the intake is the quickest way to find these.
2. MAF Sensor Contamination
The MAF sensor in the intake duct upstream of the turbo measures incoming air. The Integra's PCV system routes oil vapor back through the intake, and over time this can coat the MAF's hot-wire element. Aftermarket oiled air filters (common among Integra enthusiasts) accelerate this contamination. Clean with MAF-specific spray — never use carb cleaner or brake cleaner.
3. Fuel System Issues
The L15CA uses direct fuel injection with a high-pressure pump driven by the camshaft. A failing high-pressure pump, weak in-tank low-pressure pump, or partially clogged injector can limit fuel delivery. Under boost, the demand for fuel increases substantially, making marginal fuel system issues more apparent.
4. PCV Valve or Hose Issue
The PCV system manages crankcase gases on the turbocharged L15CA. A stuck-open PCV valve, cracked PCV hose, or a torn valve cover diaphragm can introduce unmetered air into the intake. Inspect the PCV valve and all connecting hoses for damage or disconnection.
Diagnostic Steps
- Scan for all DTCs and review freeze frame data
- Check long-term fuel trim values — above +10% confirms lean condition
- Perform a boost leak test on the charge air system
- Visually inspect all intercooler piping and clamps
- Clean the MAF sensor and retest
- Monitor fuel pressure via a scan tool with direct injection PIDs
Repair Cost Estimates
The Integra uses Honda-sourced components, which are generally affordable compared to luxury competitors:
- Boost leak repair (hose/clamp): $100–$350
- MAF sensor cleaning: $15–$35 (DIY)
- MAF sensor replacement: $150–$300
- High-pressure fuel pump: $400–$750
- PCV valve replacement: $60–$150
Can You Drive With P0174?
The 1.5L turbo is a relatively small engine that relies on boost to produce its power. Running lean under boost creates knock risk that the knock sensor system can only partially mitigate. Avoid aggressive driving and stay out of high-boost situations until the issue is resolved. Light commuting is acceptable short-term.
DIY Repair Potential
The Integra's engine bay is well laid out and accessible for DIY work. MAF sensor cleaning takes about 10 minutes. Checking boost piping clamps and connections is a visual and tactile inspection. A boost leak test requires a homemade adapter plate and shop air compressor, which many enthusiast communities have tutorials for. For fuel system diagnostics, professional tools are needed. If under Acura's warranty, the dealer should handle the repair at no cost.