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/InstallationFront Brake (Disc) Removal/Installation
1. Remove in the order indicated in the table.
2. Install in the reverse order of removal.
3. After installation, add brake fluid, bleed the air, and inspect for fluid
leakage..
4. Depress the brake pedal a few times, rotate the wheel by hand, and verify
that the brake does not drag.
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Afs (Adaptive Front Lighting System) Control Module
Purpose
The AFS control module calculates the target optical axis based on the vehicle
height signal and outputs the target optical axis signal to the headlight leveling
actuator.
Function
The AFS control module performs control of the AFS and headlight auto leveling.
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Front Drive Shaft Inspection
1. Inspect the connections for any looseness.
If there is any malfunction, tighten or replace the applicable part.
2. Inspect the dust boot for damage and cracks.
If there is any malfunction, replace the applicable part.
3. Move the spline and joint up and down, left ...