What Is Nissan's Best Selling Car

Alright, let's dive into a topic near and dear to Nissan enthusiasts: the best-selling model. While sales figures fluctuate annually, and vary greatly depending on the market, the Nissan Sentra, historically speaking, holds the crown as one of, if not *the* top seller globally. This article will break down the Sentra, focusing on understanding its key components and systems, making it easier for you to diagnose issues, perform preventative maintenance, or even consider modifications.

Purpose: Why Understanding the Sentra Matters

Whether you're a seasoned DIY mechanic or a budding enthusiast, understanding the inner workings of the Sentra is invaluable. Knowing the location of key components, their specifications, and how they interact allows you to:

Perform Routine Maintenance: Oil changes, spark plug replacements, filter changes – all become easier with a solid understanding of the engine layout and component locations.
Troubleshoot Problems: Instead of blindly replacing parts, you can pinpoint the source of an issue using diagnostic tools and your knowledge of the system's function.
Make Informed Modifications: Want to upgrade the suspension, exhaust, or intake? Knowing the factory specs and limitations allows you to choose compatible parts and avoid causing damage.
Save Money: Armed with knowledge, you can tackle repairs yourself, avoiding expensive shop labor costs.

Think of this article as a primer for reading and understanding a simplified technical diagram of key Sentra systems. I'll use example components, but remember to *always* consult the specific service manual for your model year Sentra for accurate information. And good news, we have a basic wiring diagram file which you can download at the end of this article!

Key Specs and Main Parts (Example: B17 Generation)

Let's take the B17 generation (2013-2019) Sentra as an example. While details will vary based on trim level and specific year, the fundamental systems are common across the range.

Engine (Example: MR18DE)

The MR18DE is a 1.8-liter inline-4 engine featuring: DOHC (Double Overhead Camshaft), CVTC (Continuously Variable Timing Control), and Multi-Point Fuel Injection (MPFI). Its purpose is to deliver adequate power while maintaining fuel efficiency. Common issues include: Crankshaft Position Sensor failure, which leads to no start conditions; and Catalytic converter issues, which drastically reduces MPG.

Cylinder Head: Contains the camshafts, valves, and spark plugs.
Cylinder Block: Houses the pistons, connecting rods, and crankshaft.
Crankshaft: Converts reciprocating motion of the pistons into rotational motion.
Pistons: Move up and down within the cylinders, compressing the air-fuel mixture.
Connecting Rods: Connect the pistons to the crankshaft.
Intake Manifold: Distributes air to the cylinders.
Exhaust Manifold: Collects exhaust gases from the cylinders.
Throttle Body: Controls the amount of air entering the engine.
Fuel Injectors: Spray fuel into the intake manifold or directly into the cylinders.
Ignition Coils: Provide the high-voltage spark needed to ignite the air-fuel mixture.
ECU (Engine Control Unit): The "brain" of the engine, controlling fuel injection, ignition timing, and other parameters.

Transmission (Example: CVT8)

The *CVT8* (Continuously Variable Transmission) offers seamless gear ratio changes, maximizing fuel economy. It utilizes a belt and pulley system to provide an infinite number of gear ratios within a specified range. However, CVTs are notoriously sensitive to fluid condition. Changing the fluid on the recommended intervals will increase the lifespan of the transmission dramatically.

Torque Converter: Transfers engine torque to the transmission.
Primary Pulley: Connected to the engine.
Secondary Pulley: Connected to the drive wheels.
Steel Belt: Connects the primary and secondary pulleys, transmitting power.
Valve Body: Controls the flow of hydraulic fluid within the transmission, regulating gear ratios.
TCU (Transmission Control Unit): Controls the CVT operation.

Suspension

Front: MacPherson strut suspension.
Rear: Torsion beam suspension.
Components: Struts/shocks, springs, control arms, sway bar.

Symbols - Reading the Technical Diagram

Technical diagrams use standardized symbols to represent different components and connections. Here's a basic rundown:

Solid Lines: Represent physical connections, such as wires or hoses.
Dashed Lines: Often indicate control signals or vacuum lines.
Ground Symbol (Looks like an upside-down Christmas tree): Indicates a connection to ground (the chassis).
Resistors (Zig-zag line): Oppose the flow of electrical current.
Capacitors (Two parallel lines): Store electrical energy.
Diodes (Triangle pointing to a line): Allow current to flow in only one direction.
Relays (Coil and switch): Electrically operated switches.
Colors: Wires are often color-coded (e.g., red for power, black for ground).
Component Icons: Simplified drawings representing the actual component (e.g., a battery icon, a motor icon).

For the downloaded wiring diagram, you'll find a legend explaining the specific symbols and abbreviations used. Take your time to study it before attempting any electrical work.

How It Works: Example - Fuel Injection System

Let's look at how the fuel injection system works, as an example:

The ECU receives signals from various sensors, including the Mass Airflow Sensor (MAF), Throttle Position Sensor (TPS), and Crankshaft Position Sensor (CKP).
Based on these inputs, the ECU calculates the optimal amount of fuel to inject.
The ECU sends a signal to the fuel injectors, opening them for a specific duration (pulse width).
The fuel injectors spray fuel into the intake manifold (or directly into the cylinders).
The air-fuel mixture is drawn into the cylinders, compressed, and ignited by the spark plugs.

A technical diagram would show the wiring connections between the ECU, sensors, fuel injectors, and other related components. It would also indicate the voltage levels and signal types involved.

Real-World Use: Basic Troubleshooting Tips

Here are some basic troubleshooting tips, leveraging your understanding of the Sentra's systems:

Engine Won't Start: Check the fuel pump relay and fuel pump fuse. Verify spark at the spark plugs. Look for error codes using an OBD-II scanner.
Rough Idle: Check for vacuum leaks, faulty spark plugs, or a dirty throttle body.
Poor Fuel Economy: Check the air filter, tire pressure, and spark plugs. A faulty O2 sensor can also contribute.
CVT Problems: Check the CVT fluid level and condition. Look for slipping or erratic shifting.

Important Note: *Always* consult the service manual for your specific Sentra model and year for detailed troubleshooting procedures and diagnostic codes.

Safety - Risky Components

Working on cars can be dangerous. Here are some components that require extra caution:

High-Voltage Ignition System: Disconnect the battery before working on the ignition system to avoid electric shock. The coils can produce upwards of 30,000 volts.
Fuel System: Relieve fuel pressure before disconnecting fuel lines to prevent fuel spills and fire hazards.
Airbag System: Disconnect the battery and wait several minutes before working near airbags to prevent accidental deployment. Incorrect handling can be extremely dangerous.
Cooling System: Never remove the radiator cap when the engine is hot, as the coolant is under pressure and can cause severe burns.
Lifting the Vehicle: Always use jack stands to support the vehicle after lifting it with a jack. Never work under a vehicle supported only by a jack.

Disclaimer: This article provides general information and should not be considered a substitute for professional advice. Always consult a qualified mechanic if you are unsure about any repair procedure.

You can download a simplified wiring diagram relevant to some Nissan Sentra systems by clicking HERE. Please remember that this diagram is for illustrative purposes only and may not be accurate for your specific vehicle. Always refer to the official service manual for your car.