Resolving Cam Sensor Signal Faults in Volvo L60G Loaders

[MikePhua]

The Volvo L60G and Its Electronic Control Architecture
The Volvo L60G wheel loader, part of the G-series launched in the early 2010s, was designed to meet Tier 4 emissions standards while improving fuel efficiency, operator comfort, and diagnostic capability. With a D6H engine and electronically controlled common rail fuel system, the L60G integrates multiple ECUs (Electronic Control Units) to manage engine performance, emissions, and hydraulic response. Volvo Construction Equipment, a division of the Volvo Group founded in 1832, has sold tens of thousands of G-series loaders globally, with the L60G serving in municipal, quarry, and industrial applications.
At the heart of the engine management system is the E-ECU, which monitors camshaft position via a waveform sensor. This cam signal is critical for fuel injection timing, combustion efficiency, and fault detection. When the ECU fails to read the cam signal, the engine may still run—but with degraded performance and active fault codes.
Understanding Fault Code SE2703-3 and Cam Signal Inputs
Fault SE2703-3 indicates that the ECU is not receiving a valid camshaft signal. The cam sensor in Volvo loaders typically generates an alternating current (AC) waveform, which is interpreted by the ECU through two dedicated pins: A45 (positive) and A46 (negative). These inputs are essential for synchronizing fuel injection with crankshaft rotation.
Terminology:

• ECU (Electronic Control Unit): A microprocessor-based system that controls engine and machine functions.
  
• Camshaft sensor: A device that detects camshaft position using magnetic or Hall-effect principles.
  
• AC waveform: A signal that alternates polarity, used in passive sensors to indicate rotational position.
  

In a documented case, two aftermarket ECUs—both programmed for the L60G—failed to read the cam signal. Upon inspection, the harness plug lacked the A46 pin, meaning the negative side of the waveform was not connected. This omission rendered the sensor input incomplete, triggering the fault code and causing the engine to run poorly.
Why Some ECUs Omit the A46 Pin
The missing A46 pin suggests that the aftermarket ECU was designed for a different application—possibly a machine that uses a single-wire cam sensor or a different sensor type altogether. While the E-ECU part number 60100011 is used across multiple Volvo machines, the pin configuration may vary depending on model and engine variant.
Possible reasons for omission:

• ECU configured for a machine with Hall-effect cam sensor requiring only one signal wire
  
• Cost reduction in aftermarket harness manufacturing
  
• Mislabeling or cross-application of ECU intended for L90G or excavator variant
  

Recommendations:

• Verify ECU pinout against Volvo Prosis documentation for the specific model
  
• Confirm that both A45 and A46 are populated in the harness and ECU connector
  
• Use an oscilloscope to confirm waveform presence at the sensor and ECU input
  
• Contact ECU supplier with detailed pinout and fault code information
  

DevTool and Parameter Configuration Limitations
DevTool is a diagnostic and configuration software used by Volvo technicians to adjust ECU parameters, calibrate sensors, and update firmware. However, its use is typically restricted to authorized dealers, and aftermarket ECUs may not support full DevTool functionality.
Limitations include:

• Inability to remap pin assignments
  
• Restricted access to sensor input configuration
  
• Lack of support for fault code suppression or override
  

In one case, a technician attempted to use DevTool to reassign cam sensor inputs but found that the aftermarket ECU did not support parameter changes for waveform inputs. This reinforces the need to match ECU hardware to machine-specific wiring.
Field Experience and Dealer Support
Operators with experience across E, F, G, and H series Volvo loaders report that the G-series is particularly sensitive to ECU faults and sensor mismatches. In one anecdote, a grader technician spent three days diagnosing a similar issue, only for a Volvo dealer technician to resolve it in 20 minutes using proprietary tools and documentation.
This highlights the value of dealer support when dealing with complex electronic faults. While aftermarket solutions may offer cost savings, they often lack the precision and compatibility required for seamless operation.
Conclusion
Cam sensor signal faults in Volvo L60G loaders are often caused by mismatched ECU pin configurations, especially when using aftermarket replacements. The absence of the A46 pin in the ECU harness prevents proper waveform interpretation, triggering fault SE2703-3 and degrading engine performance. To resolve the issue, technicians must verify pinouts, confirm sensor signal integrity, and ensure ECU compatibility with the machine’s wiring architecture. In electronically controlled loaders, precision matters—and even a single missing pin can silence the signal that keeps the engine in sync.