P0420 on Ram vehicles The catalytic converter on bank 1 is not cleaning up the exhaust as well as it should
P0420 is named on 7 Ram model years (2018–2026): 14 manufacturer filings and 0 owner reports in NHTSA’s files, across 1500, 3500, 2500, ProMaster.
Which Ram model years name P0420
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports |
|---|---|---|---|
| 2019 Ram 1500 | Electrical System | 4 | — |
| 2026 Ram 3500 | Electrical System | 3 | — |
| 2026 Ram 2500 | Power Train | 2 | — |
| 2025 Ram 3500 | Electrical System | 2 | — |
| 2025 Ram 2500 | Electrical System | 1 | — |
| 2019 Ram ProMaster | Engine | 1 | — |
| 2018 Ram ProMaster | Power Train | 1 | — |
A model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.
Ram filings that name P0420
Source: NHTSA manufacturer communicationsBulletins and campaigns Ram filed with NHTSA whose summary names P0420. Quote the document number at the service desk — it is a diagnosis the maker has already written down.
- 1808823 Service bulletin2023-08-11 · Power Train — Manual Transmission — Control Module (Tcm/Pcm/Tecm)
- Flash: Powertrain Control Module (PCM) Updates Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or more of the following Diagnostic Trouble Codes (DTCs) have been set:? P0420 - Catalyst System Efficiency Below Threshold Bank 1. ? P0430 - Catalyst System Efficiency Below Threshold Bank 2. This bulletin involves re
- 1808723 Service bulletin2023-08-11 · Engine And Engine Cooling — Exhaust System
- Flash: Powertrain Control Module (PCM) Updates Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or more of the following Diagnostic Trouble Codes (DTCs) have been set: ? P0420 - Catalyst System Efficiency Below Threshold Bank 1. ? P0430 - Catalyst System Efficiency Below Threshold Bank 2. This bulletin involves r
- 18-033-25 Service bulletin2025-06-25 · Electrical System
- Flash: Powertrain Control Module (PCM) Updates *Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0420 - Catalyst System Efficiency Below Threshold Bank 1. ● P0430 - Catalyst System Efficiency Below Threshold Bank 2.** ● P0456 - EVAP System Small Leak. ● P06EF - Engine Restar
- 18-002-26 Service bulletin2026-01-16 · Power Train
- Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0420 - Catalyst System Efficiency Below Threshold Bank 1. ● P0430 - Catalyst System Efficiency Below Threshold Bank 2. Customers may also experience the following: ● Catalyst damage
- S2625000003 Service bulletin2026-03-31 · Electrical System
- Active/Pending Diagnostic Trouble Code (DTC) P24A0, P2482, P2481, P0420, P2470, P2471, P2472, P242D, P242B, P244D, P1484, P106D, P1060 And/or P354B Setting In The Powertrain Control Module (PCM)
- S2625000004 Service bulletin2026-03-31 · Electrical System
- Active/Pending Diagnostic Trouble Code (DTC) P24A0, P2482, P2481, P0420, P2470, P2471, P2472, P242D, P242B, P244D, P1484 And/or P214D setting In The Powertrain Control Module (PCM)
- 18-073-26 Service bulletin2026-07-22 · Engine
- Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle exhibit/set SYMPTOM: one or more of the following Diagnostic Trouble Codes (DTCs): ● P0420 - Catalyst System Efficiency Below Threshold Bank 1. ● P0430 - Catalyst System Efficiency Below Threshold Bank 2. ● P0556 - Brake Booster Pressure Sensor Circuit Performanc
What P0420 means
Source: SAE J2012 / OBD-IIThe catalytic converter on bank 1 is not cleaning up the exhaust as well as it should.
A stored code names the test that failed, never the part that caused it. The record above is what Ram and its owners have filed about it; the code’s page across every make has the whole file.
Common questions
Source: NHTSA files and the OBD-II standardIs P0420 a known problem on Ram vehicles?
It is a documented one: NHTSA's files hold 14 manufacturer filings and 0 owner reports naming P0420 on 7 Ram model years (2018–2026). Whether it is a problem on one particular car is a diagnosis, not a count — but a bulletin that names the code on your model year is the place to start.
Which Ram models does P0420 appear on most?
2019 1500 (4 documents), 2026 3500 (3 documents), 2026 2500 (2 documents).
Does P0420 on a Ram mean it is recalled?
No. Recalls are filed by campaign and matched by VIN; no recall is triggered by a scan tool. Check the VIN at nhtsa.gov/recalls, or open the model year's page here for the campaigns filed against it.