Manitou MRT 1840 Alarm 33 Diagnosis and System Recovery

[MikePhua]

The MRT 1840 and Its Rotational Telehandler Innovation
The Manitou MRT 1840 is a rotating telehandler designed for multi-function lifting, material handling, and aerial access. With a maximum lift height of 18 meters and a load capacity of 4,000 kg, it combines the reach of a crane with the maneuverability of a forklift. Introduced as part of Manitou’s MRT series, the 1840 model integrates advanced hydraulic control, electronic safety systems, and a 360-degree rotating turret—allowing operators to work efficiently in confined or complex environments.
Manitou, founded in France in 1958, has become a global leader in rough-terrain handling equipment. The MRT line was developed to meet the needs of construction, industrial maintenance, and logistics sectors where versatility and compact footprint are essential. With over 10,000 units sold globally, the MRT 1840 remains a flagship model in the rotating telehandler category.
Terminology Clarification

• Telehandler: A telescopic handler used for lifting and placing loads at height or distance.
  
• Rotating turret: A base mechanism allowing the upper structure of the machine to rotate independently of the chassis.
  
• Alarm 33: A diagnostic fault code indicating a specific system error, often related to hydraulic or electronic control.
  
• CAN bus: A communication protocol linking electronic control units across the machine.
  

Understanding Alarm 33 and Its Implications
Alarm 33 on the MRT 1840 typically signals a fault in the hydraulic or electronic control system. While the exact meaning may vary slightly by software version, it often relates to:

• Hydraulic pressure anomalies in the boom or turret rotation circuit
  
• Sensor miscommunication or failure in the load management system
  
• CAN bus interruption between joystick, ECU, and hydraulic controller
  
• Safety interlock breach preventing movement or function activation
  

When Alarm 33 is triggered, the machine may enter a restricted mode, disabling boom movement, rotation, or auxiliary hydraulics. In some cases, the engine may continue running, but lifting functions are locked out to prevent unsafe operation.
A technician in Alberta encountered Alarm 33 during a cold-weather lift. After inspecting the hydraulic pressure sensor and reseating the CAN bus connector, the fault cleared and full functionality was restored.
Diagnostic Strategy and Inspection Sequence
To resolve Alarm 33, follow a structured diagnostic path:

• Check hydraulic fluid level and inspect for contamination or aeration
  
• Inspect pressure sensors and verify voltage output against spec
  
• Scan the ECU for fault codes using a Manitou-compatible diagnostic tool
  
• Test CAN bus continuity and termination resistance
  
• Verify safety interlock status including stabilizer deployment and boom angle sensors
  

Recommended tools:

• Hydraulic pressure gauge with quick-connect fittings
  
• Multimeter with CAN bus diagnostic capability
  
• OEM service manual with wiring and hydraulic schematics
  
• Diagnostic laptop or handheld scanner with MRT software
  

A contractor in Georgia used a diagnostic scanner to trace Alarm 33 to a failed turret rotation sensor. After replacing the sensor and recalibrating the system, the machine resumed full operation.
Component Replacement and Calibration Procedures
If a faulty component is identified:

• Replace pressure sensors with OEM-rated units
  
• Clean and reseat all electrical connectors using contact cleaner
  
• Update ECU firmware if available from dealer support
  
• Recalibrate boom angle and load sensors using service mode
  
• Reset alarm codes and test full range of motion
  

Tips:

• Use torque specs from the service manual for sensor installation
  
• Avoid mixing hydraulic fluids that may affect sensor readings
  
• Label connectors during disassembly to prevent miswiring
  
• Perform a full function test after repairs to verify system integrity
  

A fleet manager in British Columbia added a sensor log to his MRT units, tracking replacement intervals and calibration history. This reduced downtime and improved fault resolution speed.
Preventive Measures and Operator Best Practices
To avoid future Alarm 33 incidents:

• Inspect hydraulic and electrical systems monthly
  
• Keep connectors dry and protected from vibration
  
• Train operators to recognize early warning signs such as sluggish movement or flickering indicators
  
• Avoid operating in extreme cold without preheating hydraulic fluid
  
• Maintain clean battery terminals and stable voltage supply
  

Operator tips:

• Deploy stabilizers fully before lifting to satisfy interlock conditions
  
• Avoid abrupt joystick movements that may spike hydraulic pressure
  
• Use diagnostic mode periodically to check system health
  
• Report any alarms immediately and log conditions for technician review
  

A crew in Texas implemented a pre-shift checklist that included sensor status and fluid inspection. This proactive approach reduced alarm-related downtime by 70% over one season.
Conclusion
Alarm 33 on the Manitou MRT 1840 is a safeguard against unsafe or compromised operation. While it may seem cryptic, it reflects the machine’s commitment to precision and protection. With disciplined diagnostics, proper component care, and operator awareness, the fault can be resolved efficiently—restoring the telehandler’s full capabilities. In high-reach handling, safety and control are inseparable, and Alarm 33 is a reminder that smart machines demand smart maintenance.