What P0171 Means on Your 2020 Dodge Charger
A P0171 code on your 2020 Dodge Charger tells you the powertrain control module has detected a lean air-fuel mixture on Bank 1. The 2020 Charger is available with the 3.6L Pentastar V6, 5.7L HEMI V8, or the 6.4L 392 HEMI V8. On the supercharged 6.2L Hellcat, this code can also appear but is less common due to the forced induction. A lean condition means there is too much air or not enough fuel reaching the cylinders on Bank 1.
The Charger's performance-oriented engines are sensitive to air-fuel ratio changes. Let us walk through the diagnosis and repair process.
Symptoms
- Check engine light on
- Rough or unstable idle
- Hesitation during acceleration
- Reduced fuel economy
- Possible misfires at low RPM
- Engine may feel down on power
Common Causes
- Vacuum Leak (35% likelihood) - The Pentastar V6 and HEMI V8 both use composite intake manifolds that can develop gasket leaks. PCV hoses, brake booster lines, and other vacuum connections can also crack or come loose.
- MAF Sensor Contamination (25% likelihood) - Oil from aftermarket air intakes or general contamination can affect MAF accuracy. This is especially common on Chargers with aftermarket cold air intakes.
- Fuel Delivery Issue (25% likelihood) - A weakening fuel pump or dirty injectors can starve the engine of fuel. The 5.7L and 6.4L HEMI engines have high fuel demands.
- Exhaust Leak Before O2 Sensor (15% likelihood) - An exhaust manifold leak upstream of the Bank 1 oxygen sensor can draw in air and falsely indicate a lean condition. HEMI exhaust manifold bolts are known to loosen.
Diagnostic Steps
- Scan for all codes. Check for P0174, misfire codes, or O2 sensor codes.
- Monitor fuel trims. LTFT above +10% on Bank 1 confirms the lean state. Higher at idle versus cruise suggests a vacuum leak.
- Inspect the intake system. Check all vacuum hoses, the PCV valve, and intake manifold gaskets.
- Smoke test. Use a smoke machine to find hidden vacuum leaks.
- Clean or test MAF sensor. Use MAF-specific cleaner.
- Check fuel pressure. The 5.7L HEMI should hold about 58 psi at idle.
Repair Costs
- Vacuum leak repair: $75 - $350. Hoses are cheap. Intake manifold gasket is more involved.
- MAF sensor service: $15 - $280. Clean first. OEM replacement costs $180 to $280.
- Fuel pump replacement: $400 - $850. In-tank pump requires tank removal.
- Exhaust manifold repair: $250 - $700. Bolt retorque is cheap; manifold replacement is more.
Performance Considerations
If you have a modified Charger with an aftermarket intake, exhaust, or tune, these modifications can contribute to P0171. Aftermarket oiled air filters are notorious for contaminating MAF sensors. If you have a tune, the fuel tables may need adjustment. Always inform your mechanic about any modifications.
Prevention Tips
- Use quality dry air filters, especially with aftermarket intakes
- Run Top Tier gasoline to keep injectors clean
- Inspect vacuum hoses and exhaust manifold bolts periodically
- Address check engine lights before they cause secondary damage
- Keep up with regular maintenance schedules