Jeep Wrangler 2018 — technical service bulletin
Bulletin 1803621 · NHTSA communication 10221200 · issued Apr 15, 2021
Technical service bulletin
communication type
Exterior Lighting
component
2018
model years
1
vehicle entries
Official summary
Flash: Powertrain Control Module (PCM) Updates This bulletin involves reprogramming the PCM with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may f Customers may comment on one or more of the following: Excessive fan noise when the A/C is on MAX output. Rough idle at engine start up in colder ambient temperatures. The following software enhancements are also included in this update : Electric Vacuum Pump (EVP) update. Fan noise reduction. Low Speed Pre Ignition (LSPI) update.
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.