Diagnosing Tram Failure in the John Deere 110 TLB

[MikePhua]

John Deere 110 TLB Background and Market Role
The John Deere 110 Tractor Loader Backhoe (TLB) was introduced in the early 2000s as a compact yet powerful machine designed for utility contractors, landscapers, and municipalities. With a hydrostatic transmission, four-wheel drive, and a 43-horsepower diesel engine, the 110 TLB offered the versatility of a tractor with the digging capability of a backhoe. Deere, founded in 1837, positioned the 110 as a bridge between agricultural compact tractors and full-size construction backhoes. Thousands of units were sold across North America, especially in rental fleets and small excavation outfits.
Symptoms of Tram Failure and Code 11
A common issue reported by operators involves intermittent loss of tram (drive) function. In one case, the machine gradually lost forward and reverse movement until it failed completely. The onboard diagnostic system flashed a “Code 11,” which corresponds to “no sensor supply voltage.” This error disables the hydrostatic drive system, rendering the machine immobile.
Typical symptoms include:

• Sudden loss of forward and reverse movement
  
• Engine runs normally, hydraulics remain functional
  
• Diagnostic display shows Code 11
  
• No prior warning or gradual degradation
  
• Issue may be weather-dependent or triggered by vibration
  

Terminology Clarification

• Tram: Refers to the drive or propulsion system of the machine.
  
• Hydrostatic Transmission: A fluid-based drive system that uses hydraulic pressure to control speed and direction.
  
• Ground Speed Sensor: Measures wheel rotation to inform the ECU of travel speed.
  
• Engine Speed Sensor: Monitors RPM and helps coordinate drive logic.
  
• ECU (Electronic Control Unit): The onboard computer that manages engine, transmission, and safety systems.
  

Root Causes of Code 11 and Tram Loss
Code 11 typically indicates that the ECU is not receiving voltage from one or more critical sensors. This can be caused by:

• Loose or corroded sensor connectors
  
• Damaged wiring harness due to abrasion or rodent activity
  
• Failed sensor (ground speed or engine speed)
  
• Faulty ECU or internal logic error
  
• Poor grounding or battery voltage instability
  

In one documented case, the operator planned to unplug and replug both the ground speed and engine speed sensors to reset the signal. This is a valid first step, especially if the issue is intermittent and environmental factors like moisture or vibration are involved.
Recommended Diagnostic Steps
To isolate and resolve tram failure:

• Inspect all sensor connectors for corrosion, looseness, or bent pins
  
• Use dielectric grease to improve contact and prevent future oxidation
  
• Check wiring harness for damage, especially near the transmission and under the cab
  
• Test sensor output using a multimeter or diagnostic tool
  
• Verify battery voltage and ground continuity to the ECU
  
• Reset the ECU by disconnecting the battery for 10 minutes
  

If the sensors are functional and wiring is intact, the ECU may need to be replaced or reprogrammed. In rare cases, vibration or heat can cause internal ECU faults that only appear intermittently.
Field Anecdote and Practical Insight
A technician in West Virginia encountered a similar issue on a 110 TLB used for trenching. After losing tram function during a rainstorm, he discovered that the ground speed sensor connector had filled with water due to a cracked boot. Drying and resealing the connector restored full function. He later added a rubber shield to prevent future ingress.
Another operator in Arizona found that his machine would lose drive only during hot afternoons. After replacing the engine speed sensor, the issue disappeared. The original sensor had degraded internally and failed under thermal load.
Preventive Measures and Long-Term Reliability
To maintain tram performance and avoid sensor-related failures:

• Inspect and clean all electrical connectors every 250 hours
  
• Replace sensor boots and seals if cracked or brittle
  
• Use zip ties or conduit to protect exposed wiring
  
• Keep a spare ground speed sensor in the tool kit
  
• Document error codes and conditions for future reference
  

Conclusion
Tram failure in the John Deere 110 TLB, especially when accompanied by Code 11, is often caused by sensor voltage loss due to corrosion, wiring damage, or environmental stress. By methodically inspecting connectors, verifying sensor output, and maintaining clean electrical pathways, operators can restore drive function and prevent future shutdowns. As compact machines become more electronically integrated, attention to sensor health and diagnostic codes becomes essential for uptime and safety.