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Service bulletin 18-029-20 REV. 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 id10176582
Published by NHTSA2020-06-22
Manufacturer's number18-029-20 REV. A
Manufacturer's date2020-05-19
NHTSA componentPOWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); ELECTRICAL SYSTEM; ENGINE

NHTSA's 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 find the following DiagnosticTrouble Code (DTC) has been set:U0100 - Lost Communication With ECM/PCM. In addition, the customer may also experience the following: The vehicle will not crank if the ECM gets hotter than 50 °C (122°F).

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

Electrical system, Engine, Transmission and driveline, Automatic transmission, Transmission control module

Trouble codes named

U0100

Vehicles listed
FIAT 500X2019

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

Other bulletins for the same vehicles and component
18039212022-09-26. Service bulletin. 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 find the following DTChas been set: P2110 - Electronic Throttle Control System Bank 1 - Forced Limited RPM. P2173 - High Airflow/Vacuum Leak Detected (Slow Accumulation). U0100 - Lost Communication With ECM/PCM. The following DTCs have been changed from a one trip fault to a two trip fault: P0607 - ECU Internal Performance. In addition, the customer may also experience the following: The vehicle will not crank if the ECM gets hotter than 50 °C (122°F).
18-029-202020-04-27. Service bulletin. 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 find the following DiagnosticTrouble Code (DTC) has been set:U0100 - Lost Communication With ECM/PCM. In addition, the customer may also experience the following:The vehicle will not crank if the ECM gets hotter than 50 °C (122 °F).