The Automatic Speed Control Device (ASCD) switch in Nissan vehicles is an essential component of the cruise control system. This switch allows drivers to activate and manage cruise control settings directly from the steering wheel. When functioning correctly, it provides a convenient way to maintain speed without continuous foot pressure on the accelerator. However, issues can arise, leading to diagnostic trouble codes such as P1564, which indicates a fault with the ASCD steering switch. Understanding how this system operates and how to troubleshoot common issues can help drivers maintain their vehicle’s performance effectively.
| Key Terms | Description |
|---|---|
| ASCD | Automatic Speed Control Device |
| P1564 | Diagnostic trouble code indicating ASCD steering switch fault |
The ASCD system integrates several components, including the ASCD steering switch, which is typically located on the steering wheel. This switch includes buttons for setting speed, canceling cruise control, and adjusting speed settings. When any of these components malfunction, it can trigger warning lights or prevent the cruise control from functioning properly.
In this article, we will explore the functionality of the ASCD switch, common issues associated with it, troubleshooting steps, and solutions for repairing or replacing faulty components.
Understanding the ASCD System
The ASCD system in Nissan vehicles is designed to enhance driving comfort by allowing drivers to maintain a steady speed on highways or long stretches of road. The system operates through a series of sensors and switches that communicate with the vehicle’s Engine Control Module (ECM).
Components of the ASCD System
- ASCD Steering Switch: Located on the steering wheel, this switch includes buttons for activating cruise control, setting speed, canceling cruise control, and adjusting speed.
- ECM: The brain of the vehicle that processes inputs from various sensors and controls engine functions accordingly.
- Speed Sensors: These sensors monitor vehicle speed and relay information to the ECM to maintain the set speed.
- Brake Switch: This switch signals when the brakes are applied, which automatically disengages cruise control for safety.
How It Works
When a driver activates cruise control using the ASCD switch, the ECM receives this input and adjusts throttle position to maintain the desired speed. If any component in this system fails—such as a faulty switch or sensor—the ECM may not receive accurate data, leading to error codes like P1564.
Common Issues with ASCD Switches
Several problems can cause malfunctioning of the ASCD system. Recognizing these issues early can prevent further complications.
Symptoms of ASCD Malfunction
- Cruise Control Not Engaging: The most common symptom is that pressing the cruise control button does not activate the system.
- Check Engine Light: A persistent check engine light may indicate an issue with the ASCD switch or related components.
- Erratic Speed Control: If cruise control engages but does not maintain a steady speed, there may be an issue with sensors or wiring.
Diagnostic Trouble Code P1564
The P1564 code specifically points to an issue with the ASCD steering switch. This could be due to:
- Faulty wiring or connectors
- A malfunctioning ASCD switch
- Issues within the ECM itself
Troubleshooting Steps for P1564 Code
When faced with a P1564 code, several diagnostic steps can help pinpoint the problem.
Step 1: Check Fuses
Begin by inspecting all relevant fuses associated with the cruise control system. A blown fuse can disrupt power supply to critical components.
Step 2: Inspect Wiring and Connectors
Examine wiring harnesses connected to the ASCD switch for signs of damage or corrosion. Ensure all connectors are secure and free from debris.
Step 3: Test Voltage at Switch
Using a multimeter, check for voltage at the ASCD steering switch terminals while pressing each button. Each button should produce a different voltage reading based on its function:
- Cruise Control On/Off
- Set Speed
- Cancel
- Accelerate/Resume
If readings are inconsistent or absent, it suggests a faulty switch.
Step 4: Check Brake Switch Functionality
Ensure that the brake switch is functioning correctly. If it fails to signal when brakes are applied, it may prevent cruise control from engaging properly.
Step 5: Replace Faulty Components
If testing indicates a malfunctioning ASCD steering switch or wiring issues, replacement may be necessary. Genuine Nissan parts are recommended for optimal performance.
Repairing or Replacing ASCD Components
When repairs are needed for an ASCD issue, understanding how to replace components safely is crucial.
Replacing the ASCD Steering Switch
1. Disconnect Battery: Always disconnect the battery before working on electrical components to prevent accidental airbag deployment.
2. Remove Airbag (if applicable): Follow manufacturer instructions carefully to remove any airbag components safely.
3. Access Steering Wheel Assembly: Remove screws securing the steering wheel cover and carefully detach it from the assembly.
4. Disconnect Old Switch: Unplug connectors from the old ASCD steering switch and remove it from its mounting location.
5. Install New Switch: Connect the new switch and secure it in place before reassembling any removed components.
6. Reconnect Battery: Once everything is back in place, reconnect the battery and test functionality.
Testing After Replacement
After replacing any component in the ASCD system:
- Start your vehicle and check if any warning lights appear.
- Test each function of your new ASCD steering switch.
- Ensure that cruise control engages smoothly at various speeds.
FAQs About Ascd Switch Nissan
- What does P1564 mean?
P1564 indicates a fault with the Automatic Speed Control Device (ASCD) steering switch. - How do I reset my Nissan’s cruise control?
You can reset it by disconnecting your battery for a few minutes or using an OBD-II scanner. - Can I drive my Nissan with a P1564 code?
While you can drive it, it’s advisable to address this code as it affects your cruise control functionality. - Where is the ASCD switch located?
The ASCD switch is typically located on your vehicle’s steering wheel. - What should I do if my cruise control won’t engage?
Check fuses, inspect wiring connections, and test your ASCD steering switch for faults.
In conclusion, understanding how to diagnose and address issues related to your Nissan’s ASCD system can significantly enhance your driving experience. Regular maintenance checks and prompt attention to warning codes like P1564 will ensure that your vehicle remains safe and reliable on all journeys.