U0284 on the 2018 Subaru Impreza
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.
| 07-140-18 | 2018-12-10. Service bulletin. This bulletin announces an additional troubleshooting step to follow when diagnosing a DTC U0284: ?LOST COMMUNICATIONWITH ACTIVE GRILLE SHUTTER MODULE ?A?. Water intrusion into the harness wiring leading to connector B63 for the Active Grille Shutter (AGS) may lead to corrosion of the harness wiring and / or connector terminals and result in a communication loss with the ECM. |
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| 07-140-18 | 2018-12-10. Service bulletin. This bulletin announces an additional troubleshooting step to follow when diagnosing a DTC U0284: ?LOST COMMUNICATIONWITH ACTIVE GRILLE SHUTTER MODULE ?A?. Water intrusion into the harness wiring leading to connector B63 for the Active Grille Shutter (AGS) may lead to corrosion of the harness wiring and/or connector terminals and result in a communication loss with the ECM. |
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.