How Do You Remote Start Your Car

Remote starting your car used to be a luxury, but it's becoming increasingly common, even standard, on many vehicles. Understanding how it works can be incredibly useful for troubleshooting issues, diagnosing problems, and even installing aftermarket systems. This article provides a detailed explanation of the inner workings of a remote start system, assuming you have a basic understanding of automotive electronics. We'll break down the key components, explain the wiring, and offer some basic troubleshooting advice.

Purpose of Understanding the Remote Start System

Why bother learning about remote start systems? Well, a comprehensive understanding can be invaluable for several reasons:

Troubleshooting: When your remote start system malfunctions, knowing the underlying principles can save you a trip to the mechanic. You can pinpoint potential issues with the wiring, modules, or even the remote itself.
DIY Installation: If you're considering installing an aftermarket remote start system, this knowledge is crucial. While installation can be complex, understanding the wiring diagrams and system logic will significantly increase your chances of success.
Modification and Upgrades: Understanding the system's architecture allows you to explore potential modifications or upgrades. Perhaps you want to integrate it with a smart home system or add additional security features.
Understanding Vehicle Security: Remote start systems interact directly with your car's security system. Knowing how they integrate helps you understand the overall vulnerability and security measures of your vehicle.

Key Specs and Main Parts of a Remote Start System

A typical remote start system comprises several key components, each with its specific function:

Remote Transmitter (Key Fob): This is the device you use to initiate the remote start sequence. It transmits a radio frequency (RF) signal to the receiver.
Remote Receiver/Control Module: This module receives the RF signal from the remote transmitter and processes it. It verifies the signal, checks safety parameters, and initiates the starting sequence. This is the brain of the system.
Bypass Module (Transponder Bypass): This module is essential for vehicles with immobilizer systems. The immobilizer prevents the car from starting without the correct key present. The bypass module temporarily emulates the key's transponder signal, allowing the remote start to bypass the immobilizer.
Wiring Harness: This is the network of wires that connects all the components. The wiring is usually specific to the vehicle make and model.
Hood Pin Switch: This is a safety switch that prevents the remote start from activating if the hood is open. It's a crucial safety feature to prevent accidental starting during maintenance.
Brake Pedal Switch Interface: This ensures the remote start disengages if the brake pedal is pressed, another important safety feature.
Tachometer Input (or Data Bus Interface): This monitors the engine's RPM to ensure the engine has started successfully. Some systems use a tachometer signal; others communicate via the vehicle's data bus (CAN bus).

Understanding Wiring Diagram Symbols

Reading wiring diagrams is essential for understanding how a remote start system is wired. Here's a breakdown of common symbols:

Solid Lines: Represent wires. The thickness of the line may indicate the gauge (thickness) of the wire.
Dashed Lines: Can indicate shielded wires, ground connections, or connections that are optional.
Circles: Represent connections. A filled circle typically indicates a permanent connection, while an open circle might indicate a connector.
Squares and Rectangles: Represent components like relays, switches, and modules.
Resistor Symbol (Zig-zag line): Represents a resistor, which limits current flow.
Capacitor Symbol (Two parallel lines): Represents a capacitor, which stores electrical energy.
Diode Symbol (Triangle pointing to a line): Represents a diode, which allows current to flow in only one direction.
Ground Symbol (Stacked lines tapering down): Represents a ground connection, which provides a return path for current.
Battery Symbol (Long and short parallel lines): Represents a battery, the power source.
Colors: Wires are often color-coded to help identify them. Common colors include Red (power), Black (ground), Yellow, Blue, Green, White, and Brown.

How a Remote Start System Works

The remote start process unfolds in a specific sequence:

Remote Activation: You press the remote start button on the key fob. The transmitter sends an RF signal to the receiver module in the car.
Signal Verification: The receiver module verifies the signal. This often involves checking for a specific code to prevent unauthorized access.
Safety Check: The receiver module checks safety parameters. Is the hood closed (hood pin switch)? Is the brake pedal depressed? Is the car in park/neutral? If all conditions are met, the system proceeds.
Immobilizer Bypass: If the vehicle has an immobilizer, the bypass module is activated. This temporarily provides the signal required to start the engine.
Starter Activation: The receiver module activates the starter relay. This sends power to the starter motor, cranking the engine.
Engine Monitoring: The system monitors the engine RPM via the tachometer input or data bus. If the engine starts successfully, the starter is disengaged.
Run Time: The engine runs for a pre-programmed amount of time, typically 10-15 minutes. The system can usually be shut down by pressing the remote start button again, or by pressing the brake pedal.

Real-World Use: Basic Troubleshooting Tips

Here are some common problems and troubleshooting tips:

Remote Not Working:
- Check the battery in the remote.
- Ensure the remote is programmed to the receiver module. Consult your owner's manual or the remote start system's manual for programming instructions.
- Check for interference. Other RF devices can sometimes interfere with the signal.
Car Doesn't Start:
- Check the hood pin switch. Make sure it's properly installed and functioning.
- Check the brake pedal switch interface. Ensure it's not falsely triggering, preventing the start.
- Verify the immobilizer bypass module is functioning correctly. The car's security light might provide clues.
- Check the wiring connections. Ensure all wires are securely connected and not damaged.
Engine Starts and Stalls:
- Check the tachometer input or data bus connection. The system might not be getting an accurate RPM signal.
- Check for fuel or ignition system issues. The remote start system can only start the engine; it can't fix underlying mechanical problems.

Safety Considerations

Working with automotive electrical systems can be dangerous. Here are some key safety points:

Disconnect the Battery: Always disconnect the negative battery terminal before working on any electrical components. This prevents accidental shorts and potential damage to the vehicle's electrical system.
Airbag Systems: Be extremely cautious when working near airbag systems. Incorrect wiring can trigger airbag deployment. Consult your vehicle's service manual for specific instructions.
Fuses: Use the correct amperage fuses. Replacing a blown fuse with a higher amperage fuse can overload the circuit and cause a fire.
Wiring: Ensure all wiring connections are secure and properly insulated. Exposed wires can cause shorts and electrical hazards.
Professional Installation: If you're not comfortable working with automotive electrical systems, it's best to have the remote start system installed by a professional.

The most risky components in a remote start system installation are the high current wires going to the starter and the connections to the immobilizer bypass. Incorrect connections here can damage your vehicle's ECU or immobilizer system.

Remote start systems can be complex, but with a solid understanding of the components, wiring, and operation, you can troubleshoot issues, perform installations, and even modify your system to suit your needs. By understanding and following these steps, you can ensure that your remote start installation is done safely and effectively. We have a detailed wiring diagram available for download. This diagram provides a comprehensive overview of the remote start system's components and their interconnections. Please reach out to us and specify which vehicle make and model you are working on and we will provide a link to download the specific document.