Outline
The PCM controls energization to the starter relay according to an immobilizer system request to improve security.
While not in P or N position, the starter relay energization by the ignition key is inhibited. (ATX)
While not in neutral, the starter relay energization by the push button start is inhibited. (MTX)
Block Diagram

Operation
The PCM establishes a ground to the starter circuit. Therefore when the ignition is switched to START, the starter relay is energized and the starter motor rotates. As a result, the engine starts normally.
The PCM does not establish a ground to the starter circuit. Therefore, even if the ignition switch is turned to the start position, the starter motor does not rotate because the starter relay does not energize, and the engine does not start.

The PCM turns the starter relay off with the engine speed at the set value or more (value from engine coolant temperature fluctuates).
Refrigerant Charging
Starter Disassembly/Assembly [Skyactiv G 2.0]Mass Air Flow (MAF) Sensor/Intake Air Temperature (Iat) Sensor No.1 Removal/Installation
NOTE:
Because the IAT sensor No.1 is integrated in the MAF sensor, replacing the
IAT sensor No.1 includes replacement of the MAF sensor/IAT sensor No.1.
1. Disconnect the negative battery cable..
2. Disconnect the MAF sensor/IAT sensor No.1 connector.
3. Remove the MAF sensor/IA ...
Air Bag System Service Cautions [Standard Deployment Control System]
Air Bag System Component Disassembly
Disassembling the air bag system components could cause it to not operate
(deploy) normally. Never disassemble any air bag system components.
Air Bag Module, Pre-tensioner Seat Belt Handling
Oil, grease, or water on the air bag modules ...
Sunroof Switch Inspection
1. Disconnect the negative battery cable..
2. Remove the front map light..
3. Verify that the continuity between the sunroof switch terminals is as indicated
in the table.
If not as indicated in the table, replace the sunroof switch.
...