What Does Code P0420 Mean on a 2024 Jeep Cherokee?
A P0420 code on your 2024 Jeep Cherokee indicates the ECU has detected reduced Bank 1 catalytic converter efficiency. Note that Jeep discontinued the Cherokee after 2023 for the US market, so a 2024 model may be a late-production 2023 or a market-specific variant. The Cherokee (KL platform) was powered by either the 2.4L Tigershark MultiAir inline-4 producing 180 horsepower or the 3.2L Pentastar V6 with 271 horsepower, both with a 9-speed automatic.
If your Cherokee is still relatively new with low mileage, P0420 likely points to a sensor or software issue covered under warranty.
Common Symptoms
- Check engine light on
- Slight fuel economy decrease
- Possible sulfur smell from exhaust
- Emissions test failure
- No major performance changes
Most Likely Causes on the Cherokee
1. Faulty Downstream O2 Sensor
The oxygen sensor downstream of the catalytic converter can fail prematurely, especially on the 2.4L Tigershark engine. A defective sensor sends incorrect readings that trigger P0420.
2. PCM Software Issue
Stellantis has issued calibration updates for the Cherokee's PCM. A software update may correct the monitoring thresholds that trigger P0420.
3. Exhaust Leak
The 9-speed automatic generates more heat during frequent gear changes, and exhaust gaskets can degrade. Leaks near the O2 sensors will cause false P0420 codes.
4. Catalytic Converter Degradation
The 2.4L Tigershark engine is known for oil consumption in some units, which can contaminate the catalytic converter. The 3.2L V6 converter can also degrade at higher mileage.
How to Diagnose the P0420 Code
- Scan for all diagnostic codes including oil consumption-related codes
- Check for TSBs from Stellantis for the Cherokee platform
- Monitor upstream and downstream O2 sensor live data
- Inspect exhaust system for leaks at all connections
- For the 2.4L, check oil consumption records
Repair Options and Costs
Professional Repair
- Catalytic converter (2.4L): $800–$1,500 parts and labor
- Catalytic converter (3.2L V6): $1,000–$1,800 parts and labor
- O2 sensor replacement: $160–$300
- Exhaust leak repair: $120–$350
- PCM software update: $100–$200
DIY Considerations
If the vehicle is under warranty, let the dealer handle repairs. O2 sensor replacement is feasible for DIYers. The Cherokee has moderate access to the exhaust system for inspection and basic repairs.
Cost Breakdown Summary
- OEM converter (2.4L): $400–$900
- OEM converter (3.2L): $600–$1,200
- O2 sensor (part): $60–$170
- Labor: $200–$600
- Diagnostic fee: $100–$150
Prevention Tips
- Monitor oil consumption on the 2.4L Tigershark engine closely
- Use the recommended oil grade and change interval
- Keep PCM software up to date through dealer visits
- Address any misfire codes immediately
- Use quality fuel to maintain clean combustion