How To Start Your Car With Remote

Alright, let's dive into the inner workings of remote car starting. Understanding this system goes beyond just pressing a button; it's about grasping the intricate dance of electronics and mechanics that brings your engine to life from afar. This knowledge empowers you to troubleshoot issues, perform basic repairs, or even explore aftermarket upgrades with confidence. Think of this as your advanced user's manual for remote start systems.

Purpose: Why Understand Remote Start Systems?

This isn't just academic. Knowing how your remote start system operates allows you to:

Diagnose Problems: Is your car failing to start remotely? Understanding the system can help you pinpoint the cause, whether it's a faulty sensor or a wiring issue.
Perform Basic Repairs: Simple fixes like replacing a blown fuse or a loose connection become manageable.
Plan Upgrades: Want to add features like extended range or smartphone control? Knowing the system's architecture is crucial.
Understand Installation: If you're tackling a DIY install, this knowledge is absolutely essential.

Key Specs and Main Parts

Let's break down the core components of a typical remote start system:

Remote Transmitter (Key Fob): The handheld device that sends the start command. It operates on a specific Radio Frequency (RF), usually around 300-900 MHz.
Remote Start Module (RSM): The brain of the operation. This module receives the RF signal from the key fob, verifies its authenticity (often using rolling codes to prevent theft), and initiates the starting sequence. It contains a microprocessor, relays, and various input/output (I/O) ports.
Antenna: Located in the vehicle, the antenna picks up the RF signal from the remote transmitter.
Hood Pin Switch: A crucial safety component. If the hood is open, the remote start system is disabled to prevent accidental starting while someone is working on the engine.
Brake Pedal Switch: Another safety interlock. Pressing the brake pedal while the engine is running via remote start will typically disengage the system.
Tachometer Input: The RSM needs to monitor engine RPM to ensure the engine has started successfully and to prevent over-cranking. This signal is usually obtained from the ignition coil or the engine's ECU (Engine Control Unit).
Ignition Wires: These are the wires that normally connect to the ignition switch and control the starting, running, and accessory functions of the vehicle. The RSM intercepts and controls these functions during remote starting. Common wires include:
- Ignition 1 & 2: Power the ignition system.
- Accessory: Powers non-essential systems like the radio and climate control.
- Starter: Activates the starter motor.
CAN Bus Interface (Optional): In modern vehicles, the RSM might communicate with the car's computer network (CAN bus) to control various functions and retrieve vehicle data. CAN stands for Controller Area Network.

Symbols: Deciphering the Diagram

Understanding the symbols used in a remote start system diagram is key to interpreting it correctly. While specific symbols may vary slightly depending on the manufacturer, here are some common ones:

Solid Lines: Represent wired connections between components. Thicker lines often indicate power wires carrying higher current.
Dashed Lines: Usually represent signal wires carrying lower current or data signals.
Ground Symbol (┴): Indicates a connection to the vehicle's chassis ground (usually a metal part of the car body).
Power Symbol (+ or Battery Symbol): Indicates a connection to the vehicle's positive power supply (usually the battery).
Relay Symbol (□ with a diagonal line): Represents an electromagnetic switch used to control high-current circuits.
Resistor Symbol (zigzag line): Indicates a resistor, which limits the flow of current.
Capacitor Symbol (||): Indicates a capacitor, which stores electrical energy.
Diode Symbol (►|): Indicates a diode, which allows current to flow in only one direction.
Color Codes: Wires are often color-coded to identify their function (e.g., Red for power, Black for ground, Yellow for ignition). The diagram should include a color code legend.

Lines represent the flow of electrical signals. Color coding is important. The diagram should always have a key to what the colors mean.

How It Works: The Sequence of Events

Here's a step-by-step breakdown of how a remote start system initiates the starting sequence:

Remote Activation: You press the start button on the key fob, which transmits an RF signal to the antenna in the vehicle.
Signal Reception and Verification: The antenna receives the signal and relays it to the Remote Start Module (RSM). The RSM verifies the signal's authenticity using a pre-programmed security code (rolling codes are common).
Safety Check: The RSM checks the safety interlocks:
- Is the hood closed (hood pin switch)?
- Is the brake pedal pressed (brake pedal switch)?
If either of these conditions is not met, the starting sequence is aborted.
Ignition Activation: Assuming the safety checks pass, the RSM activates the ignition circuit by energizing the appropriate relay. This is equivalent to turning the key to the "ON" position.
Accessory Activation: The RSM energizes the accessory circuit, powering up the radio, climate control, and other non-essential systems (optional).
Starter Activation: The RSM energizes the starter circuit, causing the starter motor to crank the engine. The RSM monitors the tachometer input to determine if the engine has started.
Engine Running Monitoring: Once the engine starts, the RSM continues to monitor the tachometer input to ensure the engine is running smoothly. If the engine stalls, the RSM may attempt to restart it a few times.
Time Limit: Most remote start systems have a pre-set time limit (e.g., 15 minutes) after which the engine will automatically shut off if no further action is taken (like inserting the key and driving).

Real-World Use: Basic Troubleshooting

Here are some common problems and troubleshooting tips:

Car Doesn't Start:
- Check the Battery: Ensure the car battery is fully charged. A weak battery is a common cause of remote start failure.
- Hood Pin Switch: Verify the hood pin switch is properly installed and functioning correctly. Try manually pressing the switch to see if the system responds.
- Brake Pedal Switch: Check the brake pedal switch to make sure it's not stuck or misadjusted.
- Fuses: Check the fuses associated with the remote start system. A blown fuse is a common culprit.
- Remote Battery: Make sure the remote control's batteries are fresh.
Car Starts and Immediately Shuts Off:
- Tachometer Input: The RSM may not be receiving a valid tachometer signal. Check the connection to the ignition coil or ECU.
- Security System: Some security systems may interfere with the remote start. Consult your vehicle's manual or a professional installer.
Remote Not Working:
- Remote Battery: First step, replace the battery.
- Programming: The remote may need to be reprogrammed to the RSM. Refer to your system's manual for programming instructions.
- Antenna: Inspect the antenna and its connection to the RSM.

Safety: Handle with Care

Working with electrical systems in a car can be dangerous. Always disconnect the negative terminal of the battery before working on any wiring. Specifically, be cautious when working with:

Ignition Wires: These wires carry high voltage and current when the engine is running. Incorrect wiring can damage the engine or electrical system.
Airbag Systems: Avoid working near airbag control modules or wiring. Accidental deployment of an airbag can cause serious injury.
Fuel System: Be extremely careful when working near the fuel system. Gasoline is highly flammable.

If you're not comfortable working with electrical systems, it's best to consult a qualified professional.

We have a detailed wiring diagram available for download. This diagram will provide specific information about wire colors, connections, and component locations for a generic remote start system. Remember that wiring configurations vary depending on the vehicle and the remote start system. Always refer to the manufacturer's specific diagram for your vehicle. If you would like to download the general remote start diagram, please email [email protected] with the subject line "Remote Start Diagram Request".