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

U0284: 00 (PCM (H3T)) 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	The active air shutter operates fully.
Possible cause	Failure of active air shutter power supply system fuse Failure of harness (including connector/terminal) between sub relay and active air shutter (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Failure of harness (including connector/terminal) between active air shutter and body ground (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Failure of LIN communication harness (including connector/terminal) between active air shutter and PCM (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) Active air shutter malfunction (Refer to [ACTIVE AIR SHUTTER INSPECTION ] in service information). PCM malfunction (Refer to [PCM REMOVAL/INSTALLATION ] in 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: Observe legal speed limits when driving the vehicle and perform the procedure in a location where safety can be assured. To prevent an accident, work with another person when the vehicle is being driven (one person drives vehicle, other person operates M-MDS). Drive the vehicle at 10 km/h {6.2 mph} or more for approx. 1 min.
Courtesy of MAZDA MOTORS CORP.
1	Battery
2	Sub relay
3	Active air shutter
4	PCM