How To Auto Start Nissan Murano

Let's dive into the fascinating world of Nissan Murano's auto-start system! Whether you're tackling a repair, planning a modification, or simply curious about how this convenience feature works, understanding the auto-start system is invaluable. We'll dissect the system, explain its components, and arm you with the knowledge to troubleshoot basic issues. And remember, we have the comprehensive wiring diagram available for download to help you along the way.

Purpose and Scope

This article focuses on understanding the Nissan Murano auto-start system. A deep dive into its operation can assist in diagnosing issues related to remote starting failures, customizing the system (within safe limits, of course!), or even replacing damaged components. The goal is to provide a clear, practical understanding, not to replace a professional mechanic's expertise, but rather to empower you with the knowledge to effectively communicate with one. This information is particularly helpful when diagnosing issues like the engine not starting remotely, range problems with the key fob, or unexpected shutdowns after remote start.

Key Specs and Main Parts

The auto-start system in a Nissan Murano typically comprises the following essential components:

Remote Start Module (RSM): The brains of the operation. This module receives the signal from the key fob and initiates the starting sequence. It's typically located under the dashboard or behind the glove compartment.
Key Fob: The transmitter that sends the command to start the vehicle. These usually operate on radio frequencies, commonly 315MHz or 433.92MHz, depending on the region and model year.
Hood Switch: A safety switch that prevents the engine from starting remotely if the hood is open. This is critical to prevent injury during maintenance.
Brake Switch: Another crucial safety feature. The system verifies the brake pedal is *not* depressed during remote start, preventing unintended acceleration.
Immobilizer System: Part of the vehicle's anti-theft system. The auto-start system must communicate with the immobilizer to ensure the vehicle isn't being stolen. This typically involves a transponder in the key and a receiver in the ignition switch area.
Starter Relay: This high-current relay supplies power to the starter motor.
Wiring Harness: The network of wires connecting all the components. This is where a detailed wiring diagram becomes indispensable.
BCM (Body Control Module): Communicates with other modules and manages various vehicle functions, including some aspects of the auto-start system.

Understanding the Wiring Diagram Symbols

A wiring diagram isn't just a bunch of lines; it's a language. Let's decode some common symbols:

Lines: Indicate wiring connections. Different line thicknesses may represent different wire gauges (thicker lines usually indicate wires carrying higher current). Dashed lines often indicate shielded cables, used to reduce electromagnetic interference.
Colors: Wires are color-coded for easy identification. Common colors include red (power), black (ground), and various other colors for signal wires. The wiring diagram will include a legend explaining the color codes.
Circles: Represent connections or splices.
Rectangles: Usually represent components like relays, modules, or switches.
Ground Symbol: Typically represented by a series of decreasing horizontal lines or an inverted triangle, indicating a connection to the vehicle's chassis ground.
Diode Symbol: A triangle pointing to a vertical line. Diodes allow current to flow in only one direction.
Resistor Symbol: A zig-zag line. Resistors limit current flow.

The diagram will also indicate the pin numbers on connectors. This is crucial for identifying the correct wires to test or tap into.

How It Works: The Auto-Start Sequence

Here's a simplified breakdown of the auto-start sequence:

Key Fob Activation: You press the auto-start button on the key fob. This sends a radio frequency (RF) signal to the Remote Start Module (RSM).
RSM Verification: The RSM receives the signal and verifies that it's a valid command (e.g., checking for the correct encryption key).
Safety Checks: The RSM checks the safety interlocks: is the hood closed (hood switch)? Is the brake pedal released (brake switch)? If either of these conditions is not met, the system will not start.
Immobilizer Authentication: The RSM communicates with the vehicle's immobilizer system. This typically involves sending a challenge code to the immobilizer, which then responds with a valid response if the correct key transponder is present. This is crucial for preventing theft.
Starter Motor Engagement: If all checks pass, the RSM activates the starter relay, sending power to the starter motor. The engine cranks.
Engine Running: Once the engine starts, the RSM monitors the engine speed (RPM). Once a stable RPM is detected, the starter motor is disengaged.
Runtime: The engine will typically run for a pre-determined time (e.g., 10-15 minutes) before shutting off automatically. This is a safety feature to prevent the engine from running indefinitely if no one enters the vehicle. The engine may also shut off if the brake pedal is pressed or a door is opened (depending on the system's configuration).

Real-World Use: Basic Troubleshooting Tips

Here are some common issues and how to approach them:

Engine Doesn't Start:
- Check the Key Fob Battery: This is the most common culprit.
- Check the Hood Switch: Make sure it's properly closed and functioning. A faulty hood switch can prevent the system from starting. Use a multimeter to check for continuity when the hood is closed.
- Check the Brake Switch: Ensure the brake switch is functioning correctly. A faulty brake switch can also prevent starting.
- Check Fuses: Locate the fuses related to the auto-start system and check for blown fuses. The owner's manual or wiring diagram will indicate the location of these fuses.
- Immobilizer Issues: If the security light is flashing rapidly, there may be an issue with the immobilizer. Try using a different key.
- Remote Start Module: If all else fails, the RSM itself may be faulty. This is the most complex component to diagnose and may require professional assistance.
Short Range:
- Key Fob Battery: Again, start with the battery.
- Antenna Issues: The RSM has an antenna. Ensure it's properly connected and not damaged. Its location can affect range.
- Obstructions: Walls, buildings, and other obstructions can interfere with the RF signal.
Engine Shuts Off Immediately:
- Safety Interlocks: The hood switch or brake switch may be intermittently failing.
- Low Fuel: Some systems will shut down if the fuel level is very low.

Safety Considerations

Working with automotive electrical systems can be dangerous. Always disconnect the negative battery terminal before working on any electrical components. Be especially careful when working near the airbag system, as accidental activation can cause serious injury.

The following components require extra caution:

Airbag System: Never probe airbag wiring unless you are specifically trained to do so. Accidental activation can be extremely dangerous.
High-Current Wiring: The wiring to the starter motor carries a large amount of current. Avoid short circuits, which can cause fires or damage to the electrical system.
Immobilizer System: Tampering with the immobilizer system can render the vehicle unusable and may violate anti-theft laws.

Remember, if you are not comfortable working with electrical systems, it's always best to consult a qualified technician. Incorrect wiring can damage the vehicle's electrical system and may even create a fire hazard.

Get the Wiring Diagram!

Having the comprehensive wiring diagram for your specific Nissan Murano model is essential for accurate troubleshooting and repairs. It details the exact wire colors, connector locations, and circuit paths. We have the file available for download, which will significantly aid in your understanding and work on the auto-start system.

Good luck, and remember to prioritize safety!