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U0284 Lost Communication With Active Grille Air Shutter Module A

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modeNo

The grille shutter actuator is a LIN node of the engine controller. GM's 2018 ECM tables set U0284 when the ECM loses the LIN link to shutter 1 for 3 counts in Run with at least 11 V; it is Type B, MIL after two trips. Ford's 2024 OBD summary lists it as a continuous monitor: entry 5 s after start at 11–16 V, fault when the AGS signal is missing over 10 s. A 2020 Volkswagen analysis list treats a lit MIL with U0284 in the ECM as its own case. Water is the common cause: Subaru 07-140-18 (2017–2019 Impreza, connector B63), Ford SSM 46857 (C-Max, C1651), Hyundai 23-01-075H (Ioniq 5 actuator). Several Ford SSMs pair U0284 with generator codes U012D/U042E. Shutters stop moving; engine warm-up and drag suffer.

Likely causes

Water intrusion and corrosion at the shutter actuator connector or its harness

Fault on a shared connection, e.g. with the generator (check U012D/U042E)

Unstable power supply to the actuator

Shutter actuator A internally faulty or damaged by impact

Symptoms

Malfunction indicator lamp on
Grille shutter warning, shutters do not open or close
Check charging system message when a shared connection is affected

Repair estimate

DifficultyMediumDIY possible

Parts and labour€30–600

Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

active grille shutter module avehicle bus wiring

Related codes

U0285 U0585 P059F P05A2 U012D

References: gsi.ext.gm.com, fordservicecontent.com, static.nhtsa.gov, static.nhtsa.gov.