2021-2023 Kia Sorento, Sportage GDI Injector Misfire TSB

Kia Technical Service Bulletin (TSB) FUE066, dated September 2024, provided information regarding cylinder misfires in certain 2021-2023 Kia Sorento (MQ4a) and Sportage (NQ5, NQ5a) models equipped with the Theta III 2.5L GDI engine. This bulletin has since been superseded by FUE068/CA2505. The original TSB detailed a condition where GDI fuel injectors could be damaged, leading to various engine performance issues.

Symptoms of GDI Fuel Injector Misfire

Owners of affected 2021-2023 Kia Sorento and Sportage vehicles may experience several noticeable symptoms. These include the malfunction indicator lamp (MIL) illuminating on the dashboard, indicating a problem. The vehicle might also exhibit a no-start condition, general engine misfires, or reduced power, particularly when driving at highway speeds. If you notice these symptoms, your vehicle may be experiencing a GDI fuel injector misfire.

Diagnostic Trouble Codes (DTCs)

When a GDI fuel injector misfire occurs, the vehicle's onboard diagnostic system typically stores specific Diagnostic Trouble Codes (DTCs). These codes help technicians identify the nature and location of the misfire. The TSB specifically lists the following codes:

DTC	Description
P0300	Random/Multiple Cylinder Misfire Detected
P030100	Cylinder 1 Misfire Detected
P030200	Cylinder 2 Misfire Detected
P030300	Cylinder 3 Misfire Detected
P030400	Cylinder 4 Misfire Detected

Why the Kia Sportage GDI Injector Misfire Occurs

The root cause identified for this issue is damage to the GDI fuel injector itself. This damage can occur due to prolonged exposure to fuel containing ethanol. The Theta III 2.5L GDI engine uses a dual fuel injection system, with both low-pressure (MPI) and high-pressure (GDI) injectors independently supplying fuel to each cylinder. When the GDI injector is compromised, it can lead to the misfire conditions and associated DTCs.

Repair Strategy

The recommended repair involves the replacement of the GDI fuel injectors. The original TSB FUE066 outlined a procedure that required following a specific flowchart. Depending on the diagnostic findings, this could involve replacing all four GDI injectors to resolve the Kia Sportage GDI injector misfire.

Important Notice for Owners

Kia issued TSB FUE066 as a field fix repair program. It is important for owners to note that this type of bulletin does not typically involve customer notification. Repairs under this program are generally performed during the vehicle's warranty period. If a dealer needs to perform this repair outside of the warranty period, they will require DPSM (Dealer Parts and Service Management) approval.

What Owners Should Do

If your 2021-2023 Kia Sorento or Sportage is exhibiting symptoms of a GDI fuel injector misfire, such as a check engine light, misfires, or reduced power, it is recommended to visit an authorized Kia dealership. They can diagnose the issue, confirm the relevant DTCs, and determine if the GDI fuel injector replacement is necessary based on the current superseded bulletin FUE068/CA2505.

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Source: NHTSA ID 11019970