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

U0284: 00 (PCM (PYUL)) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	LIN communication system: Communication error between active air shutter and PCM
Detection condition	The PCM detects a communication error between PCM and active air shutter.
Fail-safe	Inhibits engine-stop by i-stop control.
Possible cause	Malfunction in wiring harness (including connector/terminal) between active air shutter and PCM (See CIRCUIT INSPECTION .) (See CONNECTOR INSPECTION .) 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 .) Active air shutter malfunction (Refer to [ACTIVE AIR SHUTTER INSPECTION ] ). PCM malfunction (Refer to [PCM REMOVAL/INSTALLATION ] ).
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. 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 two people when the vehicle is being driven (one person drives vehicle, other person operates M-MDS). Switch the ignition ON (engine on). 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