Service bulletin 21-023-20

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)
Type	Service bulletin
NHTSA id	10175158
Published by NHTSA	2020-05-18
Manufacturer's number	21-023-20
Manufacturer's date	2020-03-24
NHTSA component	BACK OVER PREVENTION; ELECTRICAL SYSTEM; POWER TRAIN

NHTSA's summary

Flash: Transmission Control Module (TCM) Updates This bulletin involves reprogramming the TCM with the latest available software. Customers may experience a loud whistle noise upon engine start up.

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

Driver assistance, Electrical system, Transmission and driveline, Backup camera

Vehicles listed
JEEP WRANGLER	2020

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

Recalls for the same vehicles and component
24V676000	2024-09-12. BACK OVER PREVENTION: SENSING SYSTEM: CAMERA; EXTERIOR LIGHTING:BRAKE LIGHTS
22V638000	2022-08-25. BACK OVER PREVENTION:DISPLAY FUNCTION
20V191000	2020-09-10. BACK OVER PREVENTION: SENSING SYSTEM: CAMERA

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
0300224	2024-03-18. Service bulletin. Front and Rear Axle Sensor Kit Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that the following Diagnostic Trouble Code (DTC) has been set: ? C1451-11 - Service Axle Locker System Customers may also comment on a Service Axle Locker message displayed in the Electronic Vehicle Information Center (EVIC) for this condition.
S2319000007	2024-01-08. Service bulletin. Squeak Noise From Dash Area When Turning The Steering Wheel.
0804523	2024-01-02. Service bulletin. Radio Over The Air Updating to 34.42 Software Version ? Mobile Wi-Fi inoperative upon start up. ? Hotspot gives 9No Internet9 connection message on phone when trying to connect to a device. This bulletin provides information regarding the latest Firmware Over The Air (FOTA) update and provides the service technician an overview of the steps a customer will need to take to complete the update. The radio software will be updated from 34.4 to 34.42.
S2025000001	2024-01-02. Service bulletin. Malfunction Indicator Lamp Illumination (MIL). Diagnostic Trouble Code (DTC) P203E ? Reductant Level Sensor 1 Circuit Intermittent-Erratic Set.
9003357	2024-01-02. Service bulletin. ADAPTER, Engine Oil Filter (Pentastar V6) For all 2014MY replace the Oil Filter Adapter (OFA). For any other MY (with mileage above 30,000) review and follow instructions from STAR Online S1809000007 REV. C available on Dealer Connect. Also, consider the following: 1) Remove OFA 2) Replace only the oil inlet O-ring and gaskets (seals kit in SOL above). 3) Re-install the OFA. For 2023MY and beyond use black O-ring. For 2022MY and prior use red O-ring. Note: When replacing OFA, it may be necessary to transfer the Oil Temp/Pressure Sensor from the old OFA to the new OFA.
9100134	2024-01-02. Service bulletin. Engine When replacing a GMET4 long block from a 2021 JL or older, you will need to carry over the injector wiring harness from the original engine, and the Fuel pressure sensor should be replaced with part number: 68212572AB.
9100247	2023-12-18. Service bulletin. ERG Hydraulic Tensioner Before replacing any FEAD components, please check FEAD belt layout as per the engine sales code. Customer complaint may include a noise from under the hood described as a squeal, screech, squeak, chirp or belt-related noise and/or noisy tensioner/pulley. Please refer to SOL# S2309000007.
S1808000152	2023-10-02. Service bulletin. CEL (Check Engine Lamp) Illuminated, P057B Brake Pedal Position Sensor Performance
9100133	2023-07-31. Service bulletin. ROCKER ARM ASSY - ROLLER ROCKER Case 1.- Before replacing the intake or exhaust rocker arms due to an abnormal ticking noise, please check that the INTAKE Hydraulic Lash Adjusters are not "collapsed". If a collapsed INTAKE HLA is found, replace all INTAKE HLAs on the suspect cylinder head (no need to replace rocker arms). The noise can occur at low or high RPMs, and at low or high temperatures. There are no Diagnostic Trouble Codes (DTC)s present. Case 2.- If the INTAKE camshaft or INTAKE rocker arm has excessive wear on the high lift profile (Rocker arm: slider, Camshaft: central lobe), replace the intake camshaft (1) in that cylinder head and all intake rocker arms (6).
S2025000001	2023-04-17. Service bulletin. Malfunction Indicator Lamp Illumination (MIL). Diagnostic Trouble Code (DTC) P203E ? Reductant Level Sensor 1 Circuit Intermittent-Erratic Set.