P20EE The selective catalytic reduction catalyst is not reducing NOx to standard
5 owner reports and 142 manufacturer filings across 35 model years from Chevrolet, Ford, GMC, Ram.
Where P20EE shows up
Source: NHTSA manufacturer communications and complaints| Model year | Filed under | Bulletins | Owner reports | Parts |
|---|---|---|---|---|
| 2020 GMC Sierra 2500HD | Power Train | 10 | 1 | |
| 2017 Ford F-250 Super Duty | Engine | 9 | — | |
| 2017 Ford F-350 Super Duty | Engine | 9 | — | |
| 2017 Ford F-450 Super Duty | Engine | 9 | — | |
| 2020 Chevrolet Silverado 2500HD | Electrical System | 8 | — | Battery → |
| 2020 Ford F-350 Super Duty | Power Train | 5 | 1 | |
| 2020 GMC Sierra 3500HD | Engine | 5 | 1 | |
| 2020 Chevrolet Silverado | Electrical System | 5 | — | Battery → |
| 2020 Ford F-250 Super Duty | Power Train | 5 | — | |
| 2020 Ford F-450 Super Duty | Power Train | 5 | — | |
| 2017 Ford Transit | Engine | 5 | — | |
| 2016 Ford Transit | Engine | 5 | — | |
| 2016 Ram 2500 | Power Train | 5 | — | |
| 2016 Ram 3500 | Power Train | 5 | — | |
| 2020 Chevrolet Silverado 3500HD | Engine | 4 | — | |
| 2018 Ford F-250 Super Duty | Engine | 4 | — | |
| 2018 Ford F-350 Super Duty | Engine | 4 | — | |
| 2018 Ford F-450 Super Duty | Engine | 4 | — | |
| 2018 Ford Transit | Engine | 4 | — | |
| 2019 Ford F-250 Super Duty | Power Train | 3 | — | |
| 2019 Ford F-350 Super Duty | Power Train | 3 | — | |
| 2019 Ford F-450 Super Duty | Power Train | 3 | — | |
| 2019 Ford Transit | Engine | 3 | — | |
| 2019 Ram 2500 | Electrical System | 3 | — | Battery → |
| 2019 Ram 3500 | Fuel/Propulsion System | 3 | — | Fuel pump → |
Showing the 25 model years where P20EE appears most; it is on file for 35 in total.
A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.
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P20EE by make
The same record, one make at a time: the model years, bulletins and owner reports that name P20EE on that maker’s vehicles.
What it gets filed under
What owners said
Source: NHTSA complaint databaseOwners’ own words, one per nameplate, scrubbed of anything identifying. These are unverified reports filed with NHTSA — they are what was said, not a finding that it was true.
A dealer "fixed" the P20EE code on this date, then the code came back a week later
The component/system that failed or malfunctioned is the SCR (Selective Catalytic Reduction) NOx Catalyst Efficiency system, triggering DTC P20EE – SCR NOx Catalyst Efficiency Below Threshold (Bank 1)
I have been getting a p20ee code showing something is wrong with SCR nox sensor 2
2016 ecodiesel has a malfunctioning EGR cooler and leaks coolant into the exhaust system thus causing several issues: CEL code P20EE, loss of coolant at a rate of 2 gallons per week, DPF issue & DEF injector issues
142 manufacturer filings name P20EE. Start with what the maker wrote down.
A code names the test that failed, not the part. A bulletin that names it is often a diagnosis someone has already written down — quote its number at the service desk.
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names P20EE.
- OTHERDOC_147 Over-the-air update2025-09-05 · Electrical System
- Powertrain Contol Module Over The Air Update to V2B (Diesel Only) Software Version (FOTA) 2025 - 2026 (DJ) RAM 2500 Pickup 2025 - 2026 (D2) RAM 3500 Pickup 2025 - 2026 (DD) RAM 3500 Cab Chassis 2025 - 2026 (DF) RAM 3500 10K Lb. Cab Chassis2025 - 2026 (DP) RAM 4500/5500 Cab Chassis Customers may experience one or more of the following: - Power Inverter (110V connection) drops out when shifting from
- S2525000001 Service bulletin2025-04-28 · Unknown Or Other
- Malfunction Indicator Lamp (MIL) Illuminated. Diagnostic Trouble Codes (DTCs) P22A1 – NOx Sensor Circuit High, Bank 1 Sensor 2, and P20EE – NOx Catalyst Efficiency Below Threshold, Setting.
- 1810122REVA Service bulletin2022-08-10 · Electrical System
- Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the Engine Control Module (ECM) / PowertrainControl Module (PCM) with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or moreof the following DTCs have been set: P0506 - Idle Control System RPM - L
- 1810122REVA Service bulletin2022-08-10 · Power Train — Automatic Transmission — Control Module (Tcm/Pcm/Tecm)
- Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the Engine Control Module (ECM) / PowertrainControl Module (PCM) with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or moreof the following DTCs have been set: P0506 - Idle Control System RPM - L
- 1810122REVA Service bulletin2022-08-10 · Electrical System
- Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the Engine Control Module (ECM) / PowertrainControl Module (PCM) with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or moreof the following DTCs have been set: P0506 - Idle Control System RPM - L
- 21-NA-214 Service bulletin2022-04-01 · Engine And Engine Cooling
- This technical bulletin provides repair information to correct a customer concern of Service Engine Soon Lamp being illuminated with DTCs P2002, P2463, P2459, P144E, P0421, P0422, P0106 P20EE, P129F, P16F3, P20FF, P226D, P249D, P249E, P11CC and / or P11D5. They may also comment on multiple transmission issues including harsh or delayed shifts, slip, surge, shudder, noise, whine, growl, shake and/o
What P20EE means
Source: SAE J2012 / OBD-IIThe selective catalytic reduction catalyst is not reducing NOx to standard.
A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.
Common questions about P20EE
Source: NHTSA files and the OBD-II standardCan I keep driving with P20EE stored?
Nobody can answer that from the code alone, and a site that does is guessing. A steady light means a fault was logged and the car should be checked soon; a flashing light means a severe misfire — slow down and get it seen as soon as possible, because severe misfire can quickly damage the catalytic converter. The safe read of this page is the mileage and the components, not permission.
Does a code mean the car is recalled?
No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.
Why do the counts here differ from other sites?
Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.
Will clearing the code fix it?
Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.