Purpose, Function
By lengthening the exhaust passage, the transmission of exhaust pressure waves to other cylinders can be delayed, and the amount of gas exhausted from a cylinder and forced back inside the combustion chamber is reduced By reducing the residual gas, the temperature inside the combustion chamber is reduced and the occurrence of knocking even at a high compression ratio is inhibited.
Construction
The exhaust manifold is installed to the rear of the engine. In addition, the catalytic converter (WU-TWC) is integrated (WU-TWC).

When the No.1 cylinder is at the intake stroke, the No.3 cylinder is at the exhaust stroke. By inducing the high temperature gas exhausted from the No.3 cylinder into the No.1 cylinder, the high temperature gas in the No.1 cylinder remains. If the amount of residual gas is high, the temperature in the combustion chamber rises and knocking can easily occur. With the 4-2-1 exhaust system, the transmission of exhaust pressure waves between each cylinder is delayed by the long exhaust pipes.

Exhaust System Removal/InstallationStarter Relay [Skyactiv G 2.0]
Purpose, Function
The starter relay supplies power to the starter by receiving the signal from
the PCM.
Construction
The starter relay is installed to the relay and fuse block.
Operation
The contact point is on when the voltage is supplied to the coil based on
...
Air Bag System Service Warnings [Standard Deployment Control System]
Air Bag Module Inspection
Inspecting an air bag module using a tester can operate (deploy) the air
bag module, which may cause serious injury. Do not use a tester to inspect an
air bag module. Always use the on-board diagnostic function to diagnose the
air bag module for malfunctions ...
Fuel Gauge Sender Unit Removal/Installation [Awd]
WARNING:
Always keep sparks and flames away from fuel when servicing the fuel system.
Fuel can be easily ignited which could cause serious injury or death, and damage
to equipment.
Fuel line spills and leakage from the pressurized fuel system are dangerous.
Fuel can ignite a ...