Nissan Push Start Not Working

The Nissan Intelligent Key system, commonly referred to as the 'push-to-start' system, offers convenience and security. However, like any complex electronic system, it's not immune to failures. When your Nissan's push start button refuses to cooperate, it can be frustrating. This guide delves into the inner workings of the system and outlines common causes and troubleshooting steps.

Understanding the Nissan Intelligent Key System

At its core, the Nissan Intelligent Key system is a sophisticated combination of electronic components, including:

• The Intelligent Key (Key Fob): This device contains a microchip that transmits a unique identification code. It houses the remote start, lock, unlock, and panic functions. Its primary function is two-fold: communicate with the vehicle for authentication and operate as a physical key for emergencies in some models.
• The Key Receiver/Antenna: Strategically located within the vehicle (often in the dashboard and/or center console), these antennas receive the signal emitted by the Intelligent Key. There are typically multiple antennas to ensure reliable communication regardless of the key's position within the cabin.
• The Smart Control Unit (SCU): This is the brain of the system. It receives the signal from the key receiver, verifies the key's ID against a stored list of authorized keys, and communicates with other vehicle systems, like the Engine Control Unit (ECU) and Body Control Module (BCM).
• The Push Start Button: A momentary switch that signals the SCU to initiate the starting sequence. It's more than just a button; it's an integral part of the security system.
• The Steering Lock Mechanism: An electronic lock that prevents steering when the vehicle is off. The SCU controls its engagement and disengagement.
• The Engine Control Unit (ECU): Responsible for managing the engine's operation, including fuel injection, ignition timing, and starting. The SCU authorizes the ECU to allow the engine to start.
• The Body Control Module (BCM): Manages various electronic functions within the vehicle, including door locks, lights, and the immobilizer system.
• Immobilizer System: This is a crucial anti-theft component. The ECU will not allow the engine to start unless it receives a valid code from the key via the SCU.

When you press the push start button, here's what ideally happens:

1. The key receiver detects the Intelligent Key's signal.
2. The key receiver relays the signal to the SCU.
3. The SCU verifies the key's ID against its stored list.
4. If the ID is valid, the SCU signals the steering lock to disengage.
5. The SCU communicates with the ECU and BCM, authorizing the engine start.
6. The ECU activates the fuel injectors and ignition system, and the engine starts.

Common Causes of Push Start Failure

Understanding the components and the starting sequence allows us to diagnose potential problems. Here are the most common culprits:

1. Weak or Dead Key Fob Battery

This is the most frequent cause. The Intelligent Key relies on a battery (usually a CR2032) to transmit its signal. Over time, the battery weakens, and the signal becomes too faint for the receiver to detect. Solution: Replace the key fob battery. It's a simple and inexpensive fix.

2. Interference

Radio frequency (RF) interference can disrupt the communication between the key fob and the vehicle. Sources of interference include: other electronic devices, strong radio transmitters, and even certain types of metallic objects placed near the key fob. Solution: Try moving the key fob to a different location within the vehicle or holding it directly against the push start button (some models have an emergency start feature that utilizes NFC/RFID when the battery is very low).

3. Faulty Key Fob

The key fob itself can malfunction due to physical damage, water damage, or internal component failure. Solution: Try using a spare key fob if you have one. If the spare works, the original key fob is likely the problem. If neither works, the issue lies elsewhere.

4. Steering Lock Malfunction

A faulty steering lock mechanism can prevent the engine from starting, even if the key is recognized. The SCU relies on feedback from the steering lock to confirm its disengagement. Solution: In some cases, gently wiggling the steering wheel while pressing the push start button can temporarily resolve the issue. However, this is a sign of a failing steering lock that needs professional attention.

5. Smart Control Unit (SCU) Failure

The SCU is a critical component, and its failure can cripple the entire system. This can be due to software glitches, internal component failure, or corrosion. Solution: SCU issues often require professional diagnosis and reprogramming or replacement. A scan tool capable of reading Nissan-specific diagnostic codes is essential.

6. Immobilizer System Issues

The immobilizer system prevents the engine from starting unless a valid key is present. If the immobilizer malfunctions or the key is not properly programmed, the engine will not start. Solution: This usually requires reprogramming the key or the immobilizer system using a specialized diagnostic tool. A Nissan dealer or qualified locksmith is typically required.

7. Brake Switch Failure

The push start system often requires the brake pedal to be depressed before the engine will start. A faulty brake switch can prevent the system from recognizing that the brake pedal is depressed, preventing the start sequence from initiating. Solution: Check the brake lights to see if they illuminate when the brake pedal is pressed. If not, the brake switch is likely faulty and needs to be replaced.

8. Low Voltage/Dead Battery

While seemingly obvious, a low or dead car battery can prevent the push start system from functioning correctly. The system requires sufficient voltage to operate properly. Solution: Check the battery voltage and charge or replace the battery as needed. Jump-starting the car may temporarily resolve the issue, but a proper battery test is crucial.

9. Wiring Issues

Damaged or corroded wiring can disrupt the communication between the various components of the push start system. This is more common in older vehicles or vehicles that have been exposed to harsh environments. Solution: Visually inspect the wiring harnesses and connectors associated with the push start system for any signs of damage or corrosion. Repair or replace any damaged wiring.

Troubleshooting Steps

Before resorting to professional help, try these troubleshooting steps:

1. Replace the key fob battery: This is the first and easiest step.
2. Try the spare key: If the spare works, the original key fob is likely the problem.
3. Check the car battery: Ensure the battery is properly charged and in good condition.
4. Check the brake lights: Verify that the brake lights illuminate when the brake pedal is depressed.
5. Move the key fob: Try holding the key fob directly against the push start button.
6. Wiggle the steering wheel: Gently wiggle the steering wheel while pressing the push start button.
7. Check Fuses: Consult your owner's manual for fuse locations related to the starting system and intelligent key and ensure they are intact.

When to Seek Professional Help

If you've tried the troubleshooting steps and the push start system still doesn't work, it's time to consult a qualified mechanic or a Nissan dealer. They have the diagnostic tools and expertise to diagnose and repair more complex issues, such as SCU failures, immobilizer problems, and wiring issues. Trying to diagnose these issues without the proper tools and knowledge can potentially cause further damage. Remember, safety should always be your priority.