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Service bulletin 20B21-A

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10174386
Published by NHTSA2020-05-05
Manufacturer's number20B21-A
Manufacturer's date2020-04-24
NHTSA componentENGINE AND ENGINE COOLING

NHTSA's summary

In all of the affected vehicles, there are shallow pressed valve seats in the cylinder heads. This may lead to a rough idle, engine misfires with a reduction in power/torque and a check engine/wrench light illuminated.

The document

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Engine

Vehicles listed
FORD EXPLORER POLICE INTERCEPT2020 (the catalog's model; the bulletin names a series or trim of it)
FORD F-1502020
FORD TRANSIT2020

Listing a model year does not mean every vehicle of it is concerned: the document says which.

Recalls for the same vehicles and component
24V5980002024-08-09. ENGINE
20206312020-12-21. Engine
20V7880002020-12-17. ENGINE

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

Other bulletins for the same vehicles and component
SSM 552282026-10-12. Service bulletin. Some 2020-2026 Aviator/Explorer/F-150/Bronco/Ranger vehicles equipped with a 2.7L or 3.0L (non-diesel) engine may need the front engine cover removed and reinstalled for various reasons. The Workshop Manual (WSM), Section 303-01 Engine > Removal and Installation > Engine Front Cover service procedure has been updated to include a new essential special service tool (ESST) guide pin alignment tool (303-1790) that is used to align the engine front cover to the engine block, preventing the O-ring seal on the engine oil galley feed tube from getting damaged during installation.
SSM 552172026-10-06. Service bulletin. Some 2020-2024 Explorer/Aviator vehicles equipped with 3.0L EcoBoost/hybrid engine may exhibit blue or black exhaust smoke on startup for the first 5 minutes after an overnight cold soak with no illuminated malfunction indicator lamp (MIL) or powertrain diagnostic trouble codes (DTCs) present. This may be due to engine oil breaching the dynamic oil seals separating the bearing core from the turbine housing in the left side turbocharger assembly. There is a new, updated left side turbocharger oil supply tube equipped with an internal check valve to prevent the engine oil from entering turbine housing after the engine is off. Replace the existing left side turbocharger oil supply tube with the updated service part that includes the check valve (service part# L1MZ-9T516-B) or latest level part. Refer to the Workshop Manual (WSM), Section 303-04 Fuel Charging and Controls - Turbocharger > Removal and Installation > Turbocharger Oil Supply Tube LH. For claiming, use causal part 9T516 and labor operation code 9440AL.
25B512026-06-05. Other. Certain 2021-2024 Model Year Bronco, 2021-2024 Model Year Bronco Sport, 2020-2022 Model Year Corsair and Escape, 2016-2024 Model Year Explorer, 2019-2020 Model Year Fusion, 2016-2018 Model Year Focus RS, 2022-2024 Model Year Maverick, 2016-2019 Model Year MKC and 2019-2024 Model Year Ranger Vehicles Equipped with a 2.0L or 2.3L Engine and Engine Block Heater System Block Heater Replacement
SSM 547952026-05-08. Service bulletin. Some 2021-2023 F-150 vehicles equipped with a 3.5L PowerBoost engine and 2020-2026 Explorer vehicles equipped with a 3.3L hybrid engine may exhibit an illuminated powertrain malfunction (wrench) indicator with diagnostic trouble code (DTC) P0A1E stored in the powertrain control module (PCM). The vehicle may be unable to enter electric-only drive modes as expected during normal drive cycles. This may be due to the software within the belt integrated starter generator (BISG). For vehicles with this condition, follow Pinpoint Test I: Battery Isolation/Voltage Stabilization Control Circuit Carry Outance located in the Workshop Manual (WSM), Section 303-06D and repair the vehicle as necessary. Note that the BISG is on backorder status at the time of this publication and Ford is working to make parts available. Engineering is investigating this concern. Monitor PTS for updates.
SSM 543632025-11-13. Service bulletin. Some 2021-2025 Expedition/Navigator/F-150/F-Super Duty/F-53 Motorhome/F59 Commercial Stripped Chassis/F-650/F-750/Transit vehicles equipped with a 2.7L/3.5L (non hybrid)/6.8L/7.3L engine and 2021-2026 E-Series may exhibit a rattle/scraping noise from the bellhousing area on start-up. Workshop Manual (WSM), Section 303-00 Engine System - General Information > Diagnosis and Testing and 303-06 > Starting System has been updated to address this condition. Additionally, WSM, Section 303-01 > Removal and Installation > Engine to Transmission Spacer Plate has been added to address this condition. Refer to the revised WSM sections for normal diagnosis.
SSM 542692025-10-08. Service bulletin. Some 2021-2025 Expedition/Navigator/F-150/F-Super Duty/F-53 Motorhome/F59 Commercial Stripped Chassis/F-650/F-750/Transit vehicles equipped with a 2.7L,3.5L EcoBoost (non-hybrid), 3.5L Cyclone, 6.8L or 7.3L engine, may exhibit a rattle/scraping noise from the bellhousing area on start-up. Workshop Manual (WSM), Section 303-00 Engine System - General Information > Diagnosis and Testing and 303-06 > Starting System has been updated. Additionally, WSM, Section 303-01 > Removal and Installation > Engine to Transmission Spacer Plate has been added to address this condition. Refer to the revised WSM sections for normal diagnosis.
SSM 542622025-10-07. Service bulletin. Some 2019-2020 Edge/Nautilus vehicles equipped with a 2.7L EcoBoost, 2020 Aviator vehicles equipped with a 3.0L EcoBoost or 3.0L plug-in hybrid electric vehicle (PHEV) engine, 2020 Explorer vehicles equipped with a 3.0L EcoBoost, and 2020 F-150 vehicles equipped with a 2.7L EcoBoost engine may exhibit a ticking/tapping or rattle type noise from the top front cover area of the engine. This noise may occur on initial start-up after a cold soak of 6 hours or more that may last for 2-5 seconds. This may be due to an internal component of the variable cam timing (VCT) unit. If diagnostics lead to the VCTs as the source of the noise, refer to the 2024 F-150 Workshop Manual (WSM), Section 303-00 > Diagnosis and Testing > Engine > Pinpoint Test F. Pinpoint test F has been updated to include additional steps along with a video on how to identify the single affected VCT unit that requires replacement.
TSB 25-23632025-08-07. Service bulletin. Some of the vehicles listed in the Model statement above may exhibit all of the following conditions: * Lack of air flow from inoperative blower motor * Open or damaged fuse F10 in the BJB This may be due to a damaged fuse F10 (40A) in the battery junction box (BJB). ** Model secton: all gas engine (non-BEV) ***** Legacy verbiage - will be removed after completing approvals ***** Some 2020-2024 Transit all gas engine (non-BEV) vehicles may exhibit a lack of air flow due to an inoperative heating, ventilation, and air conditioning (HVAC) blower motor. This may be due to a damaged fuse F10 (40A) in the battery junction box (BJB). To correct the condition, replace the fuse F10 (position 7 in the BJB). Replace the BJB and BJB harness only if it is required with the listed service replacement part.
24N10 S12025-08-01. Other. Certain 2020-2022 Model Year Explorer Police Interceptor Utility (PIU) Vehicles Engine Block Breaches This program provides a no-cost, one-time repair (if needed) to the engine long-block for 10 years of service or 150,000 miles from the warranty start date of the vehicle, whichever occurs first.
24M01 S22025-06-03. Other. 2020 Model Year Explorer and Explorer Police Interceptor - Utility Equipped with a 3.3L Engine Replace Front Catalytic Converters If Required and Inspect Wire Harness for Runs Rough/Misfire Condition