What P0174 Means on Your 2018 Ram 1500
A P0174 code on your 2018 Ram 1500 indicates that Bank 2 is running with a lean air-fuel mixture. The 2018 Ram 1500 offers the 3.6L Pentastar V6 (305 hp), the 5.7L HEMI V8 (395 hp), and the 3.0L EcoDiesel V6. On V-configuration gas engines, Bank 2 is the side that doesn't contain cylinder 1. Too much air or too little fuel on that bank triggers this code.
At this age, the 2018 Ram 1500 may have 60,000+ miles, making wear-related issues more common. Rubber hoses, gaskets, and sensors degrade with heat cycling and mileage.
Symptoms
- Check engine light on
- Rough idle
- Reduced power and throttle response
- Poor fuel economy
- Engine hesitation or stumble
- Knocking or pinging under load
Most Common Causes
- Exhaust Manifold Leak (30% likelihood) – The 5.7L HEMI is notorious for broken exhaust manifold bolts, especially on the passenger side (Bank 2). An exhaust leak upstream of the O2 sensor creates a false lean reading.
- Vacuum Leak (25% likelihood) – Aging intake hoses, PCV hose, and intake manifold gaskets can crack or shrink, allowing unmetered air into the engine.
- MAF Sensor Degradation (25% likelihood) – After years of service, the MAF sensor loses accuracy. Oil contamination accelerates the degradation.
- Fuel System Wear (20% likelihood) – Fuel injectors can become partially clogged. The fuel pump can weaken with age, reducing fuel pressure.
Diagnosis
- Listen for exhaust ticking – A ticking sound on cold start that fades when warm is a classic sign of broken HEMI exhaust manifold bolts.
- Compare bank fuel trims – If only Bank 2 LTFT is high, look at Bank 2-specific components.
- Smoke test – Find intake vacuum leaks.
- MAF sensor test – Clean and verify readings.
- Fuel pressure test – Check pump output and injector balance.
Repair Costs
- Exhaust manifold bolts/gasket – $200–$500. Full manifold replacement: $400–$900.
- Vacuum leak repair – $50–$400.
- MAF sensor – Cleaning: $10. Replacement: $80–$200.
- Fuel pump – $250–$500.
- Fuel injectors – Cleaning: $100–$200. Replacement: $150–$400 per injector.
DIY Feasibility
MAF cleaning and visual inspections are easy DIY jobs. HEMI exhaust manifold bolt repair can be tricky since broken bolts often need to be drilled and extracted. An experienced DIYer with the right tools can tackle it, but it requires patience. Fuel pump replacement on the Ram requires dropping the fuel tank.
Prevention
- Address exhaust ticking sounds immediately
- Replace the air filter every 20,000–30,000 miles
- Inspect intake hoses for cracks annually
- Use quality fuel consistently
- Clean MAF sensor every 30,000 miles as maintenance