What Does P0420 Mean on Your 2022 Mitsubishi Outlander?
A P0420 code on your 2022 Mitsubishi Outlander indicates that the catalytic converter on Bank 1 is not meeting efficiency standards. The 2022 Outlander was completely redesigned and now uses a 2.5L naturally aspirated four-cylinder engine (4B12) producing 181 horsepower, paired with a CVT transmission. Since this is an inline four-cylinder, there is only one bank — Bank 1 covers the entire engine.
The redesigned Outlander rides on the Nissan-Renault CMF-C platform, sharing some components with the Nissan Rogue. This means some repair solutions may be shared across these platforms.
Common Symptoms
- Check engine light on — The most obvious P0420 indicator
- Slight fuel economy decrease — Perhaps 1-2 MPG below your typical average
- Sulfur smell from exhaust — Indicates catalyst material degradation
- Normal driving behavior — The Outlander typically drives fine with this code
- Emissions test failure — Cannot pass with an active P0420
Common Causes for the 2022 Outlander
The 2022 Outlander's 2.5L engine is naturally aspirated, which generally produces lower exhaust temperatures than turbocharged engines. However, P0420 can still occur:
- Catalytic converter degradation (40% likelihood) — Even without turbocharging, the close-coupled catalytic converter can degrade over time. City driving with frequent stop-and-go conditions accelerates wear on the Outlander's converter.
- Downstream O2 sensor failure (25% likelihood) — The rear oxygen sensor can lose accuracy or fail, sending incorrect data to the ECM about converter efficiency.
- Exhaust leak (20% likelihood) — The flex pipe or gasket connections between the exhaust manifold and catalytic converter can develop leaks due to road salt, vibration, or thermal cycling.
- Engine running rich from fuel system issue (15% likelihood) — A stuck or leaking fuel injector can cause excess fuel in the exhaust, overwhelming the catalytic converter.
Diagnostic Steps
Step 1: Full OBD-II Scan
Scan for all codes. On the 2022 Outlander, pay attention to any fuel trim codes, misfire codes, or O2 sensor codes that could point to a root cause beyond the converter itself.
Step 2: O2 Sensor Data Monitoring
Use a scan tool to monitor upstream and downstream O2 sensor readings. The upstream should oscillate rapidly while the downstream should remain steady around 0.6-0.8V on a warmed-up engine.
Step 3: Exhaust Inspection
Check the entire exhaust system from the manifold through the catalytic converter. Look for rust, damage, soot marks at connections, and listen for leaks on cold start.
Repair Options and Costs
The Outlander is an affordable crossover, and repair costs reflect its mainstream positioning:
- Catalytic converter replacement: $900 - $1,800 (parts and labor). Aftermarket options are available and significantly cheaper than OEM.
- Downstream O2 sensor: $150 - $300 (parts and labor)
- Exhaust leak repair: $100 - $400 depending on location
- Fuel injector cleaning or replacement: $200 - $450
DIY Feasibility
The 2022 Outlander is more DIY-friendly than many vehicles. The O2 sensor is accessible from underneath with standard tools. Even the catalytic converter replacement is doable for an experienced home mechanic, though you will need jack stands, penetrating oil, and patience with potentially corroded fasteners.
Prevention Tips
- Use quality gasoline — Top-tier fuel with good detergent packages helps maintain clean combustion
- Follow Mitsubishi's maintenance schedule — Oil changes with 0W-20 synthetic at recommended intervals
- Avoid extended idling — Let the catalytic converter reach full operating temperature
- Address any check engine lights promptly — Small problems can cause bigger exhaust system damage if ignored