# Service bulletin 21B17

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.

- Type: Service bulletin
- NHTSA id: 10187813
- Published by NHTSA: 2021\-03\-02
- Manufacturer's number: 21B17
- Manufacturer's date: 2021\-02\-18
- NHTSA component: ELECTRICAL SYSTEM; ENGINE AND ENGINE COOLING

## NHTSA's summary

In all of the affected vehicles, the installed high\-output alternator and powertrain control module \(PCM\) calibration were not aligned. A mismatch between the alternator and PCM calibration could cause idle control issues such as engine speed fluctuations, which may cause customer dissatisfaction.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10187813-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10187813-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Electrical system, Engine

## Vehicles listed

- 2021 FORD EXPLORER

## Recalls for the same vehicles and component

- [2026005](/recalls/tc/2026005.md), 2026-01-09: Electrical
- [2025554](/recalls/tc/2025554.md), 2025-10-10: Electrical
- [2024492](/recalls/tc/2024492.md), 2024-08-23: Engine
- [24V635000](/recalls/nhtsa/24V635000.md), 2024-08-23: ENGINE AND ENGINE COOLING:ENGINE:HARD PARTS INTERNAL/MECHANICAL
- [24V598000](/recalls/nhtsa/24V598000.md), 2024-08-09: ENGINE
- [23V626000](/recalls/nhtsa/23V626000.md), 2023-09-08: ELECTRICAL SYSTEM:PROPULSION SYSTEM:TRACTION BATTERY
- [20V788000](/recalls/nhtsa/20V788000.md), 2020-12-17: ENGINE

## Other bulletins for the same vehicles and component

- [SSM 55228](/bulletins/11038440.md), 2026-10-12, Service bulletin: ENGINE; UNKNOWN OR OTHER. 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 55217](/bulletins/11038165.md), 2026-10-06, Service bulletin: ENGINE; UNKNOWN OR OTHER. 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.
- [TSB 26\-2395](/bulletins/11036595.md), 2026-09-01, Service bulletin: POWER TRAIN; UNKNOWN OR OTHER; ELECTRICAL SYSTEM. This article supersedes 26\-2287. Reason for update: update the labor operation numbers to add MT to operations C, F, G, H, J, K, L and M, and correct the part number LIMZ\-4A015\-B to L1MZ\-4A015\-B. Some of the vehicles listed in the Model statement above may exhibit at least one of the following conditions: Harsh engagement Delayed engagement Harsh shift Delayed shift Illuminated malfunction indicator lamp \(MIL\) with diagnostic trouble codes \(DTC\)s P0751, P0752, P0756, P0757, P0761, P0762, P0766, P0767, P0771, P0772, P2700, P2701, P2702, P2703, P2704, P2705, P2707, P2708, P0729, P0731, P0732, P0733, P0734, P0735, P0736, P076F, P07D9, P07F6 and/or P07F7 stored in the powertrain control module \(PCM\) or transmission control module \(TCM\). This may be due to axial movement of the CDF clutch cylinder sleeve causing hydraulic circuit leaks. NOTE: If internal transmission service is required to address a concern detected with the CDF clutch cylinder following this article, technicians should carefully inspect and replace other transmission components and flush transmission fluid cooler only as ne
- [SSM 55069](/bulletins/11036103.md), 2026-08-11, Service bulletin: VISIBILITY/WIPER; ELECTRICAL SYSTEM; STRUCTURE:BODY. Some 2020\-2025 Explorer vehicles equipped with a power roof opening panel may exhibit a sunshield with localized bunching or binding/inoperative. This may be due to a broken or missing sunshield fabric retainer/clip. A revised sunshield clip \(LJ6Z\-5452118\-B\) is now available to address this condition. It is not necessary to replace the entire sunshield assembly if the clip\(s\) are broken or missing. Refer to Workshop Manual \(WSM\), Section 501\-17 Roof Opening Panel \> General Procedures \> Inspection and Replacement of the Roof Opening Panel Shield Clip.
- [SSM55059](/bulletins/11035556.md), 2026-08-03, Service bulletin: POWER TRAIN; ELECTRICAL SYSTEM; UNKNOWN OR OTHER; FUEL/PROPULSION SYSTEM. Some 2021\-2023 F\-150 vehicles equipped with a 3.5L PowerBoost engine, 2020\-2026 Explorer vehicles equipped with a 3.3L hybrid engine, and 2020\-2023 Lincoln Aviator vehicles equipped with a 3.0L EcoBoost 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 belt integrated starter generator \(BISG\). For vehicles with this condition, follow the necessary Pinpoint Test in Workshop Manual \(WSM\), Section 303\-06 for DTC P0A1E and repair the vehicle as directed. Note that previous replacement of the BISG does not negate the need for subsequent BISG replacements if directed to do so by the appropriate Pinpoint Test diagnostics. Engineering is investigating this BISG quality concern. Monitor PTS for updates regarding this investigation.
- [26E04](/bulletins/11035465.md), 2026-08-03, Emissions: UNKNOWN OR OTHER; ELECTRICAL SYSTEM. NEW VEHICLE DELIVERY HOLD \- Emissions Recall 26E04 Certain 2021\-2025 Model Year F\-150, Maverick, Mustang, Ranger, Expedition, Bronco Sport, Explorer, Bronco, Navigator, and Aviator Vehicles Powertrain Control Module Software Update
- [25B51](/bulletins/11033577.md), 2026-06-05, Other: ENGINE. 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 54795](/bulletins/11032565.md), 2026-05-08, Service bulletin: ENGINE; ELECTRICAL SYSTEM; POWER TRAIN. 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.
- [23B64](/bulletins/11031780.md), 2026-04-30, Other: ELECTRICAL SYSTEM; FUEL/PROPULSION SYSTEM. Customer Satisfaction Program 23B64 Certain 2020\-2024 Model Year Multiple Vehicle Lines Equipped with High Voltage Batteries Battery Energy Control Module \(BECM\) Software Update
- [SSM 54756](/bulletins/11031411.md), 2026-04-21, Service bulletin: ENGINE. 2021\-2026 Explorer vehicles equipped with the 2.3L EcoBoost engine may require air conditioning \(A/C\) compressor belt removal for various reasons. The Workshop Manual \(WSM\), Section 303\-05A Accessory Drive \- 2.3L EcoBoost \> Removal and Installation \> Air Conditioning \(A/C\) Compressor Belt procedure has been revised to eliminate cutting the A/C compressor belt to remove it. Refer to the updated procedure to reuse the belt.

JSON: [/v1/bulletins/10187813](/v1/bulletins/10187813)

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