What Does P0171 Mean on a 2024 Nissan Altima?
A P0171 code on your 2024 Nissan Altima means the engine control module has detected a lean air-fuel mixture on Bank 1. The 2024 Altima is powered by a 2.5L naturally aspirated four-cylinder engine (QR25DE) producing 188 horsepower. Since this is an inline four-cylinder, Bank 1 is the only bank, meaning the entire engine is running lean.
The QR25DE has been in production for many years and is well-understood. As a 2024 model, your Altima should be under full warranty, so your first stop should be the Nissan dealer.
Symptoms You Might Notice
- Check engine light on
- Rough or uneven idle
- Hesitation during acceleration
- Slightly decreased fuel economy
- Engine may surge at steady speed
- Possible stalling in severe cases
Common Causes of P0171 on the 2024 Nissan Altima
- Vacuum Leak (30% likelihood) - Intake manifold gaskets, PCV hoses, and brake booster hoses can develop leaks. On a new vehicle, a loose factory connection is possible.
- MAF Sensor Issue (30% likelihood) - The mass airflow sensor on Nissan engines is a common P0171 trigger. Contamination or early failure can cause inaccurate readings.
- Software Calibration (20% likelihood) - Nissan may have released ECM updates that address fuel trim calibration for the 2024 Altima.
- Fuel System Component (20% likelihood) - A defective fuel pump, fuel pressure regulator, or fuel injector from the factory.
How to Diagnose the Problem
- Visit your Nissan dealer - Full warranty coverage on your 2024 Altima means free diagnosis and repair.
- Check for TSBs - Ask the dealer about any technical service bulletins related to P0171.
- Scan for codes - Pull all codes and freeze frame data to understand the conditions when the code set.
- Monitor fuel trims - LTFT above +10% confirms the lean condition.
- Visual inspection - Check for loose intake hoses or connections.
Repair Options and Cost Breakdown
- Warranty repair - $0. Full coverage on 2024 models.
- Vacuum leak repair - $80 to $300 if out of warranty.
- MAF sensor service - $50 to $250. Cleaning is cheap; replacement sensor runs $80-$150.
- ECM update - $0 to $150. Free under warranty.
- Fuel system repair - $250 to $600 out of pocket.
Can You DIY This Repair?
MAF sensor cleaning is an easy 10-minute DIY task on the Altima. However, with warranty coverage, let the dealer do it for free. Any DIY work could complicate future warranty claims.
Prevention Tips
- Use quality OEM or equivalent air filters
- Fill up with Top Tier gasoline
- Keep all scheduled service appointments at the dealer
- Report any driveability changes promptly
- Avoid aftermarket intake modifications under warranty