2021-2023 Hyundai Misfire DTC P030X GDI Injector Leak

Symptoms

Owners of certain 2021-2023 Hyundai Sonata, Santa Fe, Santa Cruz, and Tucson vehicles equipped with 2.5L GDI non-Turbo engines may experience a Hyundai misfire P030X condition. The primary symptom is the illumination of the "Check engine light (P030X)" on the dashboard, accompanied by one or more misfire Diagnostic Trouble Codes (DTCs).

Fault Codes / DTCs

This Technical Service Bulletin (TSB) specifically addresses misfire DTCs, generically referred to as P030X. This code indicates a misfire condition in one or more cylinders. Common variations include:

• P0300: Random/Multiple Cylinder Misfire Detected
• P0301: Cylinder 1 Misfire Detected
• P0302: Cylinder 2 Misfire Detected
• P0303: Cylinder 3 Misfire Detected
• P0304: Cylinder 4 Misfire Detected

These codes suggest that the engine's combustion process is not occurring correctly in the specified cylinder(s), often due to an internally leaking GDI injector.

Diagnosis / Trigger Conditions

To diagnose the Hyundai misfire P030X issue, technicians will follow a specific procedure. After confirming the presence of a P030X DTC, they will use the Global Diagnostic System (GDS) to access the "DTC Analysis" and "ENGINE" menus. It's crucial to record the DTC and Freeze Frame Data, noting which cylinder(s) are affected, before clearing the DTC.

Next, from the GDS home screen, technicians will select "Data Analysis" and then "ENGINE." The engine is then started, and the fuel pressure is monitored. If the fuel pressure drops significantly after shutting off the engine, it indicates a leaking GDI fuel injector. If the pressure does not drop, this TSB does not apply, and further misfire diagnostics are required.

Repair Procedure Summary

If a leaking GDI injector is confirmed, the repair involves replacing the affected GDI fuel injector(s). The general steps include:

1. Accessing the GDI injectors by following the detailed procedures in the shop manual under "Engine Control / Fuel System → Engine Control System → Injector Repair procedures → GDI Injector."
2. During reinstallation, new combustion seals (part number 35312-04AA0) must be installed on all reused injectors.
3. The high-pressure fuel pipe (part number 35305-2S000QQH) must be replaced with a new part after the fuel rail is reinstalled.
4. New bolts (part number 11403-08556K) are required for each replaced injector.
5. After the physical repair, the technician must upload freeze frame data for warranty claim verification.

Required Tools or Parts

To address the Hyundai misfire P030X issue, the following parts are required:

• INJECTOR ASSY-FUEL: Part Number 35310-2S000QQH (Must be replaced for any affected injector(s))
• PIPE-HIGH PRESSURE: Part Number 35305-2S000QQH (Must be replaced with new for reassembly)
• COMBUSTION SEAL RING: Part Number 35312-04AA0 (Must be replaced for any reused injector(s))
• BOLT: Part Number 11403-08556K (1-4 required, only for replaced injector(s))

Important Warnings for Owners

• Claim Documentation: For warranty claims related to TSB 23-FL-002H, it is mandatory for the repairing dealership to submit