What P0171 Means on Your 2020 Dodge Challenger
A P0171 code on your 2020 Dodge Challenger means the powertrain control module has detected a lean condition on Bank 1. The 2020 Challenger is available with the 3.6L Pentastar V6 (SXT), 5.7L HEMI V8 (R/T), 6.4L HEMI V8 (Scat Pack), and the supercharged 6.2L HEMI (Hellcat). A lean condition means the air-fuel ratio has shifted toward too much air or too little fuel on the cylinder bank containing cylinder number 1.
The Challenger is a performance car that owners often push hard, making a lean condition more concerning than on a daily driver. Let us break down the diagnosis and repair.
Symptoms
- Check engine light on
- Rough or unstable idle
- Hesitation or flat spots during acceleration
- Decreased fuel economy
- Possible misfires under load
- Engine feels sluggish compared to normal
Common Causes
- Vacuum Leak (35% likelihood) - The Pentastar and HEMI engines have multiple vacuum connections that can develop leaks. The intake manifold gasket, PCV system, and brake booster hose are common failure points.
- MAF Sensor Contamination (25% likelihood) - The Challenger is a popular platform for aftermarket cold air intakes. Oiled filter elements frequently contaminate the MAF sensor, causing lean fueling.
- Fuel Delivery Problem (25% likelihood) - A weak fuel pump or clogged injectors can cause insufficient fuel delivery, especially under heavy throttle on the V8 engines.
- Exhaust Manifold Leak (15% likelihood) - HEMI exhaust manifold bolts are known to back out over time, causing leaks that can fool the upstream O2 sensor into reading lean.
Diagnostic Steps
- Read all codes. Check for P0174, misfire codes, or O2 sensor codes.
- Monitor fuel trims. LTFT above +10% on Bank 1 confirms lean. Note idle versus cruise behavior.
- Visual inspection. Check all vacuum hoses, intake connections, and the PCV system.
- Smoke test the intake. This reveals hidden vacuum leaks efficiently.
- Clean or test MAF sensor. Use MAF-specific cleaner spray.
- Test fuel pressure. Compare to factory specs at idle and under load.
Repair Costs
- Vacuum leak repair: $75 - $350.
- MAF sensor service: $15 - $280.
- Fuel pump replacement: $400 - $850.
- Exhaust manifold repair: $250 - $700.
Performance Impact
Running lean reduces your Challenger's power output and responsiveness. More importantly, lean conditions under hard acceleration generate excessive heat that can damage pistons, valves, and catalytic converters. If you enjoy spirited driving, get this fixed before hitting the track or highway.
Prevention Tips
- Use quality dry air filters, even with aftermarket intakes
- Run premium fuel as recommended for V8 models
- Check exhaust manifold bolts periodically on HEMI engines
- Inspect vacuum hoses during routine maintenance
- Do not ignore check engine lights