Troubleshooting JLG 40 RTS Lift Not Cranking

[MikePhua]

The JLG 40 RTS is a robust and versatile rough terrain scissor lift designed for outdoor construction and maintenance work. With its high ground clearance and powerful engine, it is an essential tool for operators working in challenging environments. However, like all machinery, it can encounter problems over time. One of the more common issues operators may face is the lift not cranking, which could prevent the equipment from starting and functioning.
In this article, we will delve into the possible causes of why the JLG 40 RTS lift won’t crank, how to diagnose the problem, and the steps to take to fix it. We'll also cover preventive maintenance practices to help avoid similar issues in the future.
Understanding the JLG 40 RTS Lift
Before jumping into troubleshooting, it's helpful to understand the key components of the JLG 40 RTS. This lift is equipped with a 4WD system and is powered by a diesel or gasoline engine, depending on the model configuration. The engine powers both the hydraulic system, which operates the lift and platform, and the drive system, which allows the lift to move.
The lift's key systems include:

• Hydraulic System: Responsible for extending the platform, lifting, and tilting.
  
• Engine: Provides power to both the hydraulic and drive systems.
  
• Control Systems: Includes the ignition, safety interlock, and electrical circuits that control the operation of the lift.
  

When the lift doesn’t crank, it can be due to issues in any one of these systems.
Common Causes for a JLG 40 RTS Lift Not Cranking
Several factors can prevent the JLG 40 RTS from starting. Let’s explore the most common causes.
1. Battery Issues

• Symptoms: The lift doesn’t crank or attempts to crank but fails to start. The lights and other electrical components may appear dim or completely non-functional.
  
• Possible Causes:
  • Dead Battery: If the battery is completely discharged, the engine won't turn over. This is often the simplest explanation for the issue.
    
  • Corroded Battery Terminals: Corrosion on the battery terminals can lead to poor electrical contact, preventing the lift from starting even if the battery has charge.
    
  • Loose Battery Connections: Loose or disconnected battery cables can also prevent the engine from cranking.
    
• Solution: Start by checking the battery voltage. If the battery is low or dead, recharge or replace it. Clean the terminals and ensure the connections are tight and free from corrosion. If the battery is still in poor condition after charging, consider replacing it.
  

2. Faulty Ignition System

• Symptoms: The lift won’t crank, but you may hear a clicking sound when attempting to start. The engine may turn over very slowly or not at all.
  
• Possible Causes:
  • Ignition Switch Failure: The ignition switch can wear out or become damaged, causing a failure to send the start signal to the engine.
    
  • Starter Relay or Solenoid Failure: The starter relay or solenoid controls the electrical current to the starter motor. If either of these components fails, the engine will not crank.
    
• Solution: Inspect the ignition switch for any signs of wear or damage. Use a multimeter to test the starter relay and solenoid for continuity. If they are faulty, replace them.
  

3. Fuel System Problems

• Symptoms: The engine cranks but doesn’t start, or it starts briefly but cuts out.
  
• Possible Causes:
  • Empty Fuel Tank: Ensure the fuel tank is filled and the fuel level is sufficient for operation.
    
  • Clogged Fuel Filter: A clogged fuel filter can prevent proper fuel flow to the engine, causing it to struggle to start or not start at all.
    
  • Fuel Pump Issues: If the fuel pump is not delivering fuel to the engine, it will fail to start.
    
• Solution: Check the fuel gauge and ensure that there is enough fuel. If the tank is full, inspect the fuel filter for blockages and replace it if necessary. Listen for the fuel pump to ensure it's working properly. If it's not functioning, consider replacing it.
  

4. Hydraulic System Issues

• Symptoms: The engine turns over but the lift functions erratically, or the boom and platform won't operate properly once the engine starts.
  
• Possible Causes:
  • Low Hydraulic Fluid: If the hydraulic fluid is low or contaminated, the system may not work as intended, and the engine could struggle to crank.
    
  • Hydraulic Pump Failure: If the hydraulic pump is malfunctioning, the system may not generate enough pressure to operate the lift or the drive system.
    
• Solution: Check the hydraulic fluid levels and top them up if needed. If the fluid appears dirty or contaminated, replace it and the filters. Inspect the hydraulic pump for any signs of failure and replace it if necessary.
  

5. Safety Interlock System

• Symptoms: The engine doesn’t crank, and no electrical signals are sent to the starter motor.
  
• Possible Causes:
  • Active Safety Lockout: The JLG 40 RTS is equipped with a safety interlock system that prevents the lift from starting unless certain conditions are met, such as the platform being at the ground level, or the parking brake being engaged.
    
  • Faulty Safety Switches: If one of the safety switches (e.g., platform position switch, parking brake switch) is faulty or damaged, it can prevent the lift from cranking.
    
• Solution: Check that all safety conditions are met, including ensuring the platform is on the ground and the parking brake is engaged. Test each safety switch and replace any that are malfunctioning.
  

6. Electrical System Malfunctions

• Symptoms: The engine cranks but does not start, or the lift shows intermittent electrical faults.
  
• Possible Causes:
  • Blown Fuses: A blown fuse can cause the electrical system to malfunction, preventing the engine from cranking.
    
  • Wiring Issues: Corroded or loose wiring can prevent the electrical current from reaching the ignition or starter motor.
    
• Solution: Inspect all fuses in the electrical system and replace any that are blown. Check the wiring for signs of wear, corrosion, or disconnections, and repair or replace as needed.
  

Diagnostic Steps for Troubleshooting a Lift That Won’t Crank
To effectively diagnose and resolve the issue of a JLG 40 RTS lift not cranking, follow these steps:

1. Check the Battery: Ensure the battery is fully charged and the terminals are clean and tightly connected. If the battery is weak, replace it.
   
2. Inspect the Ignition System: Test the ignition switch, starter relay, and solenoid. If any of these components are faulty, replace them.
   
3. Fuel System Check: Verify that the fuel tank is full, and inspect the fuel filter and fuel pump. Replace any clogged or damaged parts.
   
4. Examine the Hydraulic System: Check the hydraulic fluid levels and ensure the fluid is clean. Replace the hydraulic filters and top off the fluid if necessary.
   
5. Check the Safety Interlock System: Confirm that all safety interlock conditions are met. Test each safety switch and replace any that are defective.
   
6. Inspect the Electrical System: Look for any blown fuses or loose wiring. Replace any damaged components and ensure the electrical connections are intact.
   

Preventive Maintenance Tips for the JLG 40 RTS Lift
Regular maintenance can help prevent many of the issues that could lead to the lift not cranking. Here are some preventive maintenance tips:

1. Regularly Check and Clean the Battery Terminals: Prevent corrosion and ensure proper electrical connections by cleaning the battery terminals regularly and ensuring tight connections.
   
2. Change the Fuel and Hydraulic Filters: Keep the fuel and hydraulic systems free from contaminants by changing the filters at regular intervals.
   
3. Inspect the Safety Interlock System: Regularly test the safety switches to ensure they are functioning correctly.
   
4. Keep the Fuel System Clean: Use high-quality fuel, and inspect the fuel system for blockages or leaks.
   
5. Monitor Fluid Levels: Ensure the hydraulic fluid and engine oil are at the correct levels and replace fluids at the recommended intervals.
   

Conclusion: Ensuring Reliable Performance from the JLG 40 RTS Lift
When your JLG 40 RTS lift won’t crank, it can cause significant downtime, but by following the troubleshooting steps outlined above, most issues can be resolved quickly. By addressing the battery, ignition system, fuel system, hydraulic system, and safety interlock checks, you can identify and fix the underlying cause of the issue.
Regular maintenance is the key to preventing future problems. By staying on top of routine checks and performing preventive maintenance, you can ensure your JLG 40 RTS lift continues to operate smoothly, efficiently, and safely for years to come.