2023-2024 Alfa Romeo Tonale/Dodge Hornet U0423-87 DTC

Owners of 2023-2024 Alfa Romeo Tonale and Dodge Hornet vehicles may encounter an erroneous Diagnostic Trouble Code (DTC) U0423-87. This issue is officially documented in STAR Online Publication S2308000099 Rev. A, which was released in May 2024. This technical communication from FCA (Fiat Chrysler Automobiles) addresses a specific software-related problem within the vehicle's Body Control Module (BCM).

Symptoms

The primary symptom indicating this issue is the presence of Diagnostic Trouble Code U0423-87. This code may appear as either an active fault or stored within the Body Control Module (BCM)'s memory. The full description of this specific fault is "U0423-87 Invalid Data Received from TBM (Telematic Box Module) - Missing Message Erroneously." This indicates that the BCM is incorrectly reporting a communication error with the Telematic Box Module (TBM).

Fault Codes / DTCs

This manufacturer communication specifically addresses the following diagnostic trouble code:

Diagnosis and Trigger Conditions

The Alfa Romeo Tonale U0423-87 and Dodge Hornet U0423-87 fault is observed in vehicles equipped with Body Control Module (BCM) software level 6.10. This particular software version contains a bug that causes the BCM to erroneously detect a missing message from the Telematic Box Module (TBM). Essentially, the BCM misinterprets normal communication or a lack of specific data as an error, leading to the false U0423-87 DTC being set. This is not indicative of a physical hardware failure in either the BCM or the TBM.

Important Warnings for Owners and Technicians

FCA provides a critical warning regarding this issue: "Do not replace any parts, replacement parts will perform the same unless thee software has updated." This statement is crucial because it prevents unnecessary part replacements. It clarifies that attempting to replace the Body Control Module (BCM) or the Telematic Box Module (TBM) will not resolve the U0423-87 issue if the underlying software remains unchanged. The problem is purely software-based, and new hardware with the same outdated software will simply re-exhibit the fault.

Additionally, this document serves as a record of past experiences and "does not authorize warranty repairs." Owners should be aware that while the issue is known, the specific repair process and warranty coverage should be discussed with an authorized dealership.

Repair Procedure Summary

The recommended and only effective repair for the U0423-87 DTC is a BCM service software update. This update is designed to correct the erroneous logic within BCM software level 6.10 that causes the false fault code to trigger. Technicians at an authorized dealership will use specialized diagnostic tools to flash the BCM with the updated software. This process ensures the BCM operates with the latest, corrected programming, preventing the erroneous "Invalid Data Received from TBM" message from being set.

Owner Action

If your 2023-2024 Alfa Romeo Tonale or Dodge Hornet is displaying the U0423-87 diagnostic trouble code, it is important to contact your authorized dealership. Inform them about the issue and specifically reference manufacturer communication S2308000099. This will help them quickly identify the problem and apply the correct BCM service software update. Since the issue is software-related, there are no immediate actions required by the owner other than scheduling a service appointment. The dealership will perform the necessary software update to resolve the Alfa Romeo Tonale U0423-87 problem.

Source: NHTSA ID: 11000996