What distinguishes the causes?
Keep other engine codes, leaks and identified sensor responses with the catalyst evidence. A possible wiring concern does not cancel them.
Compare the starting evidence →2020 Explorer / Police Interceptor Utility · 3.3L only
P0420 or rough running?
Separate the repair questions.
A converter finding and a wiring-related running problem are different claims. Ford’s revised 24M01 program makes the diagnosis and prior work important before deciding what comes next.
Ford 24M01 · Supplement 2 · 27 May 2025 ↗Exact engine, plant, build range and actual vehicle involvement required
WHAT DO YOU NEED TO UNDERSTAND?
YOUR NEXT DECISION
Separate the converter finding from the rough-running cause.
A code alone is not the diagnostic basis for a replacement.
Keep the applicable test result and prior work record together.
Continue with this question →
Reading context only; no finding is added.
Does the original Explorer application fit?
Optional: compare existing vehicle records. Do not guess the engine, plant or build date. No VIN is entered, and matching this table does not verify current program eligibility.
Application details remain unknown.
Could the original program cover this repair?
The May 2025 supplement states 15 years of service or 150,000 miles from the warranty start date, whichever comes first, for eligible affected vehicles and repairs. Its extra window for vehicles already over a limit ended August 31, 2025; that window is historical in 2026. Do not interpret the expired extra window as expiration of every vehicle’s underlying term.
Current involvement, mileage, start date, condition and program terms must be confirmed by the servicing Ford dealer. The page does not check eligibility, submit a VIN or promise no-cost work.
Original terms and application table ↗Take one useful question to the repair discussion
What supports each proposed repair?
Sources, revision limits and missing authority
Original Ford document read and application/decision pages checked; public document rechecked October 28, 2026. Supplement 2 supersedes Supplement 1 dated August 5, 2024. No claim that a bounded public search establishes the latest service or actual-vehicle status.
P0420 is this GoTech reading topic; the source’s catalyst condition is broader. It is not a code-triggered replacement rule. Manufacturer text and images have not been republished here. Current complete diagnostic methods, parts/installation and verification requirements, qualified review and real-vehicle evaluation remain open.
Read Ford’s original supplement ↗