2021-2023 Alfa Romeo Stelvio P0456 EVAP System Small Leak TSB

Symptoms of an EVAP System Small Leak

Owners of affected 2021-2023 Alfa Romeo Stelvio and other Stellantis vehicles may experience a "Check Engine" light illuminating on their dashboard. While a small EVAP leak might not always present noticeable driving symptoms, it can lead to increased emissions and potentially fail an emissions inspection. The specific diagnostic trouble code (DTC) associated with this issue is P0456.

Fault Codes / DTCs

The primary diagnostic trouble code addressed by this manufacturer communication is:

• P0456: "EVAP System Small Leak"

This code indicates that the vehicle's evaporative emission system has detected a very small leak, often due to a loose gas cap, a cracked hose, or a faulty component within the system.

Diagnosis and Trigger Conditions

To accurately diagnose the P0456 "EVAP System Small Leak" code, technicians are directed to perform the wiTECH Small Leak Verification Test (SLVT). This specialized diagnostic procedure, outlined in the manufacturer communication with NHTSA ID 10236933, helps pinpoint the exact location of the small leak within the evaporative emission system. The test is designed to verify the integrity of the system and ensure that any detected leaks are properly identified and addressed.

Repair Procedure Summary

The manufacturer communication details a diagnostic and repair process centered around the wiTECH Small Leak Verification Test (SLVT). This procedure involves using the wiTECH diagnostic tool to pressurize the EVAP system and monitor for pressure drops that indicate a leak. Depending on the test results, technicians will then inspect and repair or replace components within the EVAP system, such as hoses, seals, the purge valve, or the fuel tank cap, to resolve the P0456 "EVAP System Small Leak" condition.

Owner Action

If your 2021-2023 Alfa Romeo Stelvio or another Stellantis vehicle displays a "Check Engine" light with a P0456 code, it is recommended to have your vehicle inspected by an authorized service center. While a small EVAP leak is not typically an immediate safety hazard, it can affect emissions and potentially lead to other issues over time. Inform the technician about the P0456 code and mention the wiTECH Small Leak Verification Test (SLVT) as a recommended diagnostic approach.

Source: NHTSA ID 10236933