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/InstallationRelay And Fuse Block
Purpose
Relays and fuses used by each system are grouped and housed together for
smooth inspection and replacement servicing.
Function
Relays and fuses used by each system are grouped and housed together.
Construction
Installed in the engine compartment.
...
Lumber Support Motor Removal/Installation
WARNING:
Handling a side air bag improperly can accidentally operate (deploy) the
air bag, which may seriously injure you. Read the service warnings/cautions
in the Workshop Manual before handling the front seat (side air bag integrated)..
If the sliding mechanisms on both side ...
Shift Solenoid No.2 [Fw6 A EL, Fw6 Ax EL]
Purpose/Function
Shift solenoid No.2 adjusts the hydraulic pressure in the 2-6 brake circuit
based on the current demand from the TCM according to the vehicle conditions.
Construction
Shift solenoid No.2 is installed to the solenoid control valve body.
Shift solenoid N ...