What the P0420 Code Means for Your 2024 Infiniti QX60
If your 2024 Infiniti QX60 has triggered a P0420 diagnostic trouble code, the engine control module is reporting that the Bank 1 catalytic converter is not meeting its efficiency standards. The 2024 QX60 uses the same 3.5L naturally aspirated V6 engine (VQ35DD) producing 295 horsepower that was introduced in the 2022 redesign, paired with a 9-speed automatic transmission.
On a vehicle this new, a true catalytic converter failure would be unusual. The code is more likely related to a sensor issue, software calibration, or a minor exhaust system concern that is easy to address under warranty.
Symptoms You May Notice
- Check engine light on the dash — Typically the first and only symptom
- Vehicle drives normally — Most P0420 codes produce no noticeable change in performance
- Possible slight fuel economy decrease — Perhaps 1-2 MPG less than normal
- Exhaust odor — Sulfur smell is possible but unlikely on a new vehicle
Top Causes for the 2024 QX60
For a nearly new vehicle, the probability of each cause shifts compared to an older model:
- ECM software calibration sensitivity (35% likelihood) — Nissan/Infiniti may have the catalyst efficiency monitor set too aggressively. A software update from the dealer can often resolve this.
- Downstream O2 sensor defect (30% likelihood) — Even new sensors can have manufacturing defects. A Bank 1 rear O2 sensor reading outside normal parameters will trigger P0420.
- Minor exhaust leak from assembly (20% likelihood) — Factory assembly tolerances can occasionally leave a connection slightly loose, introducing unmetered air into the exhaust stream.
- Catalytic converter manufacturing defect (15% likelihood) — Rare, but covered under the federal emissions warranty regardless.
Recommended Diagnostic Steps
Step 1: Schedule a Dealer Visit
Your 2024 QX60 is fully covered under Infiniti's warranty. Take it to your nearest Infiniti dealer and report the check engine light. They will scan the codes and begin the diagnostic process at no cost to you.
Step 2: Ask About TSBs and Software Updates
Request that the technician check Nissan/Infiniti's technical database for any Technical Service Bulletins related to P0420 on the 2024 QX60. Software recalibrations are a common solution for new-model catalyst monitor issues.
Step 3: O2 Sensor Testing
If no software update is available, the dealer should test the Bank 1 downstream O2 sensor using factory diagnostic equipment. They can compare its response time and voltage range against specifications to determine if it is operating correctly.
Repair Costs
Under warranty, all repairs should be free. For reference, out-of-warranty costs would be:
- ECM software reflash: $0 under warranty ($100-$200 if out of warranty)
- O2 sensor replacement: $0 under warranty ($180-$350 if out of warranty)
- Exhaust leak repair: $0 under warranty ($150-$450 if out of warranty)
- Catalytic converter replacement: $0 under warranty ($1,400-$2,600 if out of warranty)
Warranty Information for Your 2024 QX60
Your 2024 Infiniti QX60 is covered by:
- 4-year/60,000-mile basic warranty — Covers all components including sensors and exhaust
- 6-year/70,000-mile powertrain warranty — Covers engine and related systems
- 8-year/80,000-mile federal emissions warranty — Specifically covers catalytic converters and O2 sensors
Should You DIY?
No. With a 2024 model under full warranty, there is absolutely no benefit to performing your own repairs. All P0420-related work should be done by an authorized Infiniti dealer at no charge. DIY work on emissions components could potentially void your warranty coverage.
Prevention Tips
- Use premium fuel as recommended — Infiniti recommends premium 91+ octane for the QX60
- Follow the scheduled maintenance plan — Use the Infiniti InTouch app to track service intervals
- Respond to recall and service campaign notices — These often include software updates that prevent issues like P0420
- Avoid frequently running low on fuel — Running near empty can allow sediment from the tank to reach the engine, creating combustion byproducts that stress the catalytic converter