LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mazda >> 2017 >> CX-5 Grand Select, AWD >> Repair and Diagnosis >> Engine Performance >> System >> On-Board Diagnostic - Engine Control System (4 Of 5) >> DTC U0284-00; Lin Communication System Communication Error Between Active Air Shutter And Pcm >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

DIAGNOSTIC PROCEDURE DESCRIPTION

STEP INSPECTION RESULTS ACTION
1 RECORD VEHICLE STATUS AT TIME OF DTC DETECTION TO UTILIZE WITH REPEATABILITY VERIFICATION
NOTE:
  • Recording can be facilitated using the screen capture function of the PC.
  • Record the snapshot data on the repair order.
- Go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT ACTIVE AIR SHUTTER CONNECTOR CONDITION
  • Switch the ignition off.
  • Disconnect the active air shutter connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the connector and/or terminals, then go to Step 11.
No Go to the next step.
4 INSPECT ACTIVE AIR SHUTTER POWER SUPPLY CIRCUIT FOR SHORT TO GROUND OR OPEN CIRCUIT
  • Verify that the active air shutter connector is disconnected.
  • Switch the ignition ON (engine off).
    NOTE:
    • Another DTC may be stored by the PCM detecting an open circuit.
  • Measure the voltage at the active air shutter terminal A (wiring harness-side).
  • Is the voltage B+?
Yes Go to the next step.
No Inspect the ENGINE3 15 A fuse.
  • If the fuse is blown:
    • Refer to the wiring diagram and verify whether or not there is a common connector between ENGINE3 15 A fuse and active air shutter terminal A.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
    • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to ground.
    • Replace the fuse.
    • If the fuse is damaged:
    • Replace the fuse.
  • If the fuse is normal:
    • Refer to the wiring diagram and verify whether or not there is a common connector between main relay terminal C and active air shutter terminal A.

    If there is a common connector:

  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
    • Repair or replace the malfunctioning part.

    If there is no common connector:

    • Repair or replace the wiring harness which has an open circuit.

Go to Step 11.
5 INSPECT ACTIVE AIR SHUTTER GROUND CIRCUIT FOR OPEN CIRCUIT
  • Verify that the active air shutter connector is disconnected.
  • Switch the ignition off.
  • Inspect for continuity between active air shutter terminal D (wiring harness-side) and body ground.
  • Is there continuity?
Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between active air shutter terminal D and body ground.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Inspect for the following:
    • Open circuit between active air shutter and body ground
    • Loose or lifting ground point
      • Repair or replace the malfunctioning part.

Go to Step 11.
6 INSPECT PCM CONNECTOR CONDITION
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
Yes Repair or replace the connector and/or terminals, then go to Step 11.
No Go to the next step.
7 INSPECT ACTIVE AIR SHUTTER LIN COMMUNICATION LINE FOR SHORT TO GROUND
  • Verify that the active air shutter and PCM connectors are disconnected.
  • Inspect for continuity between active air shutter terminal C (wiring harness-side) and body ground.
  • Is there continuity?
Yes Refer to the wiring diagram and verify whether or not there is a common connector between active air shutter terminal C and PCM terminal 2Z.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has a short to ground.

Go to Step 11.
No Go to the next step.
8 INSPECT ACTIVE AIR SHUTTER LIN COMMUNICATION LINE FOR SHORT TO POWER SUPPLY
  • Verify that the active air shutter and PCM connectors are disconnected.
  • Switch the ignition ON (engine off).
    NOTE:
    • Another DTC may be stored by the PCM detecting an open circuit.
  • Measure the voltage at the active air shutter terminal C (wiring harness-side).
  • Is the voltage 0 V?
Yes Go to the next step.
No If there is no common connector:
Refer to the wiring diagram and verify whether or not there is a common connector between active air shutter terminal C and PCM terminal 2Z.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to power supply.
  • Repair or replace the malfunctioning part.
  • Repair or replace the wiring harness which has a short to power supply.

Go to Step 11.
9 INSPECT ACTIVE AIR SHUTTER LIN COMMUNICATION LINE FOR OPEN CIRCUIT
  • Verify that the active air shutter and PCM connectors are disconnected.
  • Switch the ignition off.
  • Inspect for continuity between active air shutter terminal C (wiring harness-side) and PCM terminal 2Z (wiring harness-side).
  • Is there continuity?
Yes Go to the next step.
No Refer to the wiring diagram and verify whether or not there is a common connector between active air shutter terminal C and PCM terminal 2Z.
If there is a common connector:
  • Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
  • Repair or replace the malfunctioning part.

    If there is no common connector:

  • Repair or replace the wiring harness which has an open circuit.

Go to Step 11.
10 INSPECT ACTIVE AIR SHUTTER Yes Replace the active air shutter, then go to the next step.
(See ACTIVE AIR SHUTTER REMOVAL/INSTALLATION .)
No Go to the next step.
11 VERIFY DTC TROUBLESHOOTING COMPLETED Yes Repeat the inspection from Step 1.
Go to the next step.
No Go to the next step.
12 VERIFY AFTER REPAIR PROCEDURE Yes Go to the applicable DTC inspection.
(See DTC TABLE [PCM (SKYACTIV-G 2.0, SKYACTIV-G 2.5)] .)
No DTC troubleshooting completed.