DTC U0284-00: Lin Communication System: Communication Error Between Active Air Shutter And Pcm

U0284:00 (PCM - VIN Y) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	LIN communication system: Communication error between active air shutter and PCM
Detection condition	When the PCM detects a communication error between the active air shutter and the PCM.
Fail-safe	Not applicable
Possible cause	Malfunction in wiring harness (including connector/terminal) between sub relay and active air shutter (see CIRCUIT INSPECTION .) (see CONNECTOR INSPECTION .) Malfunction in wiring harness (including connector/terminal) between active air shutter and body ground (see CIRCUIT INSPECTION .) (see CONNECTOR INSPECTION .) Malfunction in LIN communication line (including connector/terminal) between active air shutter and PCM (see CIRCUIT INSPECTION .) (see CONNECTOR INSPECTION .) Active air shutter malfunction (Refer to applicable ACTIVE AIR SHUTTER INSPECTION in the service information.) PCM malfunction (Refer to applicable PCM REMOVAL/INSTALLATION (VIN Y) in the service information.)
Repeatability verification procedure	Clear the DTC recorded in the memory. (see CLEARING DTC .) Replicate the vehicle conditions at the time the DTC was detected using the following procedure. Start the engine. WARNING: While performing this step, always operate the vehicle in a safe and lawful manner. When the M-MDS is used to observe monitor system status while driving, be sure to have another technician with you, or record the data in the M-MDS using the PID/DATA MONITOR AND RECORD capturing function and inspect later. Drive the vehicle at 10 km/h {6.2 mph} or more for approx. 1 min. Perform the KOER self test. (See DTC INSPECTION .)
Courtesy of MAZDA MOTORS CORP.
1	Battery
2	Sub relay
3	Active air shutter
4	PCM