P0304 on the 2018 Toyota Highlander
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
Nobody has written a description of this code yet.
| T-SB-0148-19 | 2019-12-02. Service bulletin. TSB: Some 2017 ? 2019 model year Highlander HV vehicles may exhibit a MIL ON condition with one or more of the following Diagnostic Trouble Codes (DTCs): ? P0301 ? Cylinder 1 Misfire Detected ? P0302 ? Cylinder 2 Misfire Detected ? P0303 ? Cylinder 3 Misfire Detected ? P0304 ? Cylinder 4 Misfire Detected ? P0305 ? Cylinder 5 Misfire Detected ? P0306 ? Cylinder 6 Misfire Detected Follow the Repair Procedure in this bulletin to address this condition. |
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| T-SB-0072-19 | 2019-07-15. Service bulletin. TSB: Some 2014 ? 2018 model year Highlander and Highlander Hybrid vehicles may exhibit one or more of the following conditions. ? Various drivability concerns ? Low or no fuel pressure ? Diagnostic Trouble Codes (DTCs) (Including but not limited to P1603, P1604, P1605, P0171, P0300, P0302, P0304, U0100) ? Some 2014 ? 2018 model year Highlander Hybrid vehicles may exhibit DTC P134A. These conditions may be caused by corrosion/water in the A43 ECM connector (Highlander) or the A9 inverter water pump connector (Highlander HV). The corrosion in the A43 and A9 connectors is due to poorly sealed or damaged aftermarket windshield deicer harnesses. Follow the Repair Procedure in this bulletin to address these conditions. |
2 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.