Volvo L110H RPM Limit Problem Detailed Analysis

[MikePhua]

Machine Background
The Volvo L110H is a large-wheel loader from Volvo Construction Equipment (Volvo CE), complying with Tier 4 Final / Stage IV emissions standards. It has an operating weight roughly between 39,680 and 45,635 pounds, bucket capacities around 3.4 to 12.4 cubic yards, and delivers approximately 256 horsepower per ISO 9249 / SAE J1349 net rating.

Problem Statement
A 2015 L110H with a Volvo D8J engine (236 HP) intermittently cannot reach high RPMs. Instead, it’s stuck around 940-950 RPM, sometimes hovering there with fluctuation. When trying to accelerate, there is a lag: the pedal remains “blocked” at ~950 RPM for about a second before trying to climb. There are no errors displayed on dash or in EMS dashboard normally. However, diagnostic codes reveal multiple faults including a permanent code P06B316, and other codes related to the fuel injection / fuel system: P008700, P016F00, P008A00, P228F00, P010513.

Relevant Technical Terms & Notes

• EMS / Engine Management System: the electronic control system managing fuel, air, emissions, etc.
  
• Derate / Limiting Mode: when the engine controller reduces power or limits RPM due to detected faults to protect engine or comply with safety/emissions.
  
• Fuel Rail/System Pressure (e.g. code P0087 / “P008700”): the pressure in the common-rail fuel injection system. If too low, the engine may be starved of fuel at higher loads/speeds.
  
• P06B316: A Volvo diagnostic trouble code meaning “Sensor Power Supply ‘B’ Voltage in circuit below threshold.” It suggests that a sensor (or group of sensors) requiring the “B” supply rail is not getting enough voltage.
  

Diagnostic Findings

1. Codes that contribute to RPM limiting and performance loss
   • P008700: Fuel rail / system pressure too low. Low pressure means insufficient fuel to support higher RPMs.
     
   • P06B316: Sensor power supply “B” low. This can disable or impair sensors used by EMS to control performance, possibly triggering derate.
     
   • Other codes such as P016F, P008A, P228F etc point to injection system faults or sensor errors. Often multiple faults together will cause the system to restrict engine torque or RPM.
     
2. Symptom pattern
   • Idle is possible, but upon trying to increase RPM, there is a delay / hesitation.
     
   • RPM caps around 950 unless held at idle long, suggesting the system is in a protection or limiting mode.
     
   • Pedal position sensor (or throttle input) shows correct values in data streaming, which suggests the issue is downstream of the pedal (fuel delivery / sensors / control logic) rather than simply mechanical linkage.
     

Possible Causes
From the collected data and codes, likely causes include:

• Fuel delivery issues: low-pressure feed pump, fuel filter clogged, water in fuel, collapsed fuel line, bad connections.
  
• Sensor supply voltage issue: wiring harness or connectors feeding “sensor supply B” circuit might be loose, corroded, damaged, or shorted. This may affect sensors critical to fuel delivery, pressure sensing, throttle mapping, etc.
  
• Fuel control valve / overflow valve might be leaking or stuck, reducing rail pressure.
  
• Fuel injectors themselves could have leaks or improper functioning, affecting pressure.
  
• EMS software or firmware might be outdated or corrupt, causing misinterpretation of sensor inputs or incorrect fueling behavior.
  
• Emissions control systems could be interfering (if EGR, DPF, SCR etc sensors are not working, EMS might limit RPM).
  

Suggested Solutions / Step-by-Step Diagnostic Strategy
Here is a methodical approach to isolate and resolve the issue:

1. Read and document all fault codes, both active and stored. Confirm P06B316 is present and permanent, and that fuel rail pressure code(s) are active.
   
2. Check sensor supply circuit “B”
   • Inspect wiring harness, connectors, pin corrosion, grounding.
     
   • Measure supply voltage to sensors on that circuit with multimeter (with ignition on, engine off) to see if it meets spec.
     
   • Look for voltage drop under load.
     
3. Fuel system pressure inspection
   • Replace fuel filter(s) even if not obviously clogged.
     
   • Check feed-pump (low pressure) function.
     
   • Inspect return lines, overflow or relief valves.
     
   • Check high pressure pump behavior and its sensor(s).
     
4. Check for water or contaminants in fuel – water separation system, fuel quality.
   
5. EMS version / Software
   • Confirm what version of software is installed.
     
   • Verify if machine is Tier-compliant.
     
   • Check if emissions modifications (e.g., deletions, bypasses) were performed which might disable or corrupt emissions sensors.
     
6. Test-drive under controlled conditions after clearing codes, monitor data stream: pedal position, rail pressure, supply voltages, EGR flow etc.
   
7. Replace failing sensors / valves only after verifying faulty behavior. For example, a faulty fuel pressure sensor might mislead EMS into thinking pressure is low even though hydro-mechanical parts are working.
   

Parameter Data / Reference Values
Some useful reference values for similar Volvo loaders / engines (may differ slightly by market / engine version):

• Idle speed for L110F engine (D7E) approx 780 ± 50 RPM (low idle) and high idle ~2250 RPM when instructed.
  
• Fuel injection opening pressures, oil pressure etc specified in service guide for L110F: injectors opening pressure roughly 26.0–26.8 MPa (≈ 3770-3890 psi) for new spring type injectors.
  

Small Story / Real-World Analogy
A loader operator in a quarry once experienced similar symptoms: machine would idle, but when trying to load, RPM would hang around 900-1000 and then surge awkwardly. After several frustrating days replacing sensors at random, the real culprit turned out to be a split ring connector on the fuel supply line feeding the high pressure pump. Under load the voltage drop across that bad connection meant the pump did not get correct voltage, so the fuel rail pressure dropped, triggering derate codes. Fixing that connector restored full RPM smoothly.
Another case involved aggregated errors: a loader was aging, and corrosion on the battery-ground strap caused intermittent low sensor supply voltage, triggering sensor power supply codes, and combined with a slightly clogged fuel filter, the EMS decided to limit performance as a protective measure. Cleaning the ground strap and replacing filter resolved the problem entirely.

Development History & Corporate Context
Volvo CE has long produced the L-series wheel loaders. The “H” series, which includes L110H, represents the latest generation, incorporating stricter emissions regulation compliance (Tier 4 / Stage IV), more stringent fuel efficiency, improved operator comfort, and smarter electronics. Over decades, Volvo introduced common-rail fuel systems, advanced engine management systems (EMS), improved hydraulic linkages like OptiShift, and features such as automatic engine regeneration. These systems rely heavily on sensors and precise control. As features increase, so does the complexity, which means more potential failure points in sensors, wiring, or fuel delivery systems.
Volvo’s large wheel loaders are used globally, especially in construction, mining, quarrying. Their sales volumes are significant though exact global numbers per model year are proprietary. However, given Volvo’s reputation, issues once identified typically get addressed in service bulletins or via dealer network supports.

Conclusion
The symptom of being unable to reach full RPM in the 2015 Volvo L110H with the D8J engine appears to be caused by the interaction of:

• fuel rail pressure being too low (fuel delivery issue)
  
• a sensor power supply circuit (“B”) not delivering adequate voltage
  
• likely derate or protective mode engaged by the EMS due to these fault codes
  

To resolve, focus first on ensuring clean fuel supply, correct operation of feed pump and high-pressure pump, then verify supply voltage for sensors, inspect wiring and connectors, test sensors themselves, and ensure EMS software is up to date.