A flashing check engine light in your 2022 Dodge Challenger demands immediate attention—it means active misfiring that can damage your catalytic converters. When that flash accompanies a P0171 code indicating "System Too Lean Bank 1," you're dealing with a fuel delivery or air metering problem that's severe enough to cause combustion issues.
Understanding P0171
Your Challenger's engine needs a precise air-fuel ratio—ideally 14.7:1 for gasoline. P0171 triggers when the oxygen sensor on bank 1 (the side with cylinder 1, which is the passenger side on Hemi engines and driver's side on Pentastar V6) consistently reports that the exhaust contains too much oxygen, indicating not enough fuel is being burned.
Why Lean Causes Flashing
When the mixture is too lean, combustion temperatures rise and ignition becomes erratic. Lean misfires occur because there's insufficient fuel to sustain proper flame propagation. This creates the conditions for a flashing check engine light—the PCM's way of telling you catalytic converter damage is imminent if you keep driving.
Common Causes in the 2022 Challenger
Vacuum Leaks
Any unmetered air entering after the mass airflow sensor creates a lean condition. Common leak points on the Challenger include:
- Intake manifold gaskets
- PCV valve and associated hoses
- Brake booster vacuum line
- EVAP system connections
Mass Airflow Sensor Issues
A contaminated or failing MAF sensor underreports incoming air volume. The PCM then provides insufficient fuel for the actual air mass entering the engine. Aftermarket air filters that use excessive oil can contaminate the MAF element.
Fuel Delivery Problems
Weak fuel pump, clogged fuel filter, failing fuel pressure regulator, or dirty injectors all reduce fuel delivery. The 2022 Challenger uses a returnless fuel system where pressure is regulated at the pump—failures here affect the entire system.
Exhaust Leaks Before O2 Sensor
An exhaust leak between the engine and the upstream oxygen sensor allows atmospheric oxygen to enter the exhaust stream. The sensor reads this extra oxygen as a lean condition even if combustion was correct.
Diagnostic Steps
- Scan for all codes: Check for additional codes that might indicate the root cause.
- Check fuel trims: Long-term fuel trim (LTFT) above +15% confirms persistent lean condition.
- Smoke test: Introduce smoke into the intake system to visualize vacuum leaks.
- MAF inspection: Check for contamination, test output against known-good values.
- Fuel pressure test: Verify pressure meets specifications at idle and under load.
- Exhaust inspection: Look for soot trails around manifold connections indicating leaks.
What to Do Immediately
When the check engine light is flashing:
- Reduce speed - Slow down immediately and drive gently.
- Don't ignore it - Pull over safely as soon as practical.
- Don't shut off and restart - Repeated cold starts when misfiring causes more converter damage.
- Seek repair - Have the vehicle towed if necessary rather than driving extended distances.
Repair Costs
- Vacuum leak repair: $100-$400
- MAF sensor replacement: $150-$350
- Fuel injector cleaning: $100-$200
- Fuel pump replacement: $600-$1,000
- Catalytic converter (if damaged): $1,500-$3,500