Understanding P0174 on the 2024 Volvo S60
The P0174 diagnostic code on your 2024 Volvo S60 means the engine control module has detected that bank 2 is running lean — the combustion mixture contains too much air relative to fuel. The 2024 S60 uses Volvo's B5 mild-hybrid powertrain, which pairs a 2.0L turbocharged four-cylinder engine with a 48-volt integrated starter-generator for improved efficiency. This engine produces 247 horsepower and 258 lb-ft of torque, all managed by a sophisticated ECM that constantly monitors air-fuel ratios through oxygen sensors.
Symptoms to Expect
- Check engine light on the instrument panel
- Rough or uneven idle, sometimes accompanied by slight vibrations
- Noticeable hesitation during acceleration from stops
- Reduced fuel economy below the rated 26–35 mpg
- Potential stalling in severe cases, especially at idle
Top Causes on the 2024 S60
1. Boost Leak in Turbo Plumbing (High Likelihood)
Even on a brand-new 2024 S60, the turbo charge piping can be a source of lean codes. The pressurized air path from the turbo through the intercooler and into the intake manifold uses multiple silicone couplers and plastic charge pipes. A factory clamp that wasn't fully torqued, or a charge pipe with a minor manufacturing defect, can allow pressurized air to escape. The mild-hybrid system's frequent stop-start cycling subjects these connections to repeated thermal expansion and contraction. A smoke test at a Volvo dealer will quickly identify any leaks.
2. MAF Sensor Reading Error (Medium Likelihood)
The mass airflow sensor in the B5 engine measures incoming air so the ECM can calculate fuel delivery. On a new vehicle, outright contamination is unlikely, but an electrical fault or factory defect in the MAF sensor can cause inaccurate readings. If the MAF reports less air than is actually entering, the ECM will underinject fuel, creating the lean condition. Since this is a 2024 model, a defective MAF should be covered under warranty.
3. Fuel System Pressure Drop (Low-Medium Likelihood)
The B5 engine's direct injection system operates at extremely high pressures via a cam-driven high-pressure fuel pump. A manufacturing defect in the HPFP or fuel pressure regulator could cause intermittent pressure drops. This is rare on new vehicles but possible. Volvo scan tools can monitor real-time fuel rail pressure to verify pump performance under various load conditions.
4. Vacuum Line Disconnection (Low Likelihood)
With a new vehicle, a vacuum line that was never properly connected during assembly is a possibility. These small-diameter lines run to the brake booster, purge valve, and wastegate actuator. A disconnected or kinked line will allow unmetered air into the intake, triggering P0174. A visual inspection of all vacuum connections in the engine bay may reveal the issue.
Diagnostic Steps
- Check for TSBs and recalls — For a 2024 model year, there may be a known issue with a published fix. Your Volvo dealer can check this immediately.
- Monitor fuel trims — Use a Volvo VIDA-compatible scan tool to check STFT and LTFT on bank 2. Positive values above +8-10% indicate a lean condition.
- Smoke test the intake — Pressurize the boost system and watch for smoke escaping from connections, hoses, or gaskets.
- Verify MAF sensor output — Compare MAF readings to expected values at various RPMs using Volvo's diagnostic specifications.
- Check fuel pressure — Monitor high-pressure rail data during idle and acceleration to ensure the HPFP maintains spec.
Expected Costs (If Out of Warranty)
- Boost hose or clamp repair: $120–$400
- MAF sensor replacement: $200–$440
- High-pressure fuel pump: $700–$1,300
- Vacuum line repair: $75–$180
Warranty Information
Your 2024 Volvo S60 is covered by Volvo's 4-year/50,000-mile New Vehicle Limited Warranty. The P0174 code relates to fuel and emissions systems, which are fully covered. Additionally, the federal emissions warranty covers major emissions components for 8 years/80,000 miles. Take your S60 to the nearest Volvo dealer — this repair should be completed at no charge to you.
Is It Safe to Drive?
A lean condition is not immediately dangerous, but continued driving can stress the catalytic converter and increase exhaust temperatures. Since your 2024 S60 is under warranty, there's no reason to delay. Schedule a dealer appointment within a week to protect your vehicle and maintain your warranty coverage.