Sensors vs. actuators - a comparison of the sensory and muscular systems of modern vehicles
Modern vehicles are highly networked and technically sophisticated. Sensors and actuators have to work together perfectly for everything to function reliably: Sensors deliver the information and actuators convert it into specific movements. One does not work without the other - and workshops that understand both systems have a clear advantage when it comes to fast and precise fault diagnosis.
Measuring sensors - moving actuators
Sensors are vehicle’s sensory system. They record data such as temperature, pressure, air mass or position and transmit this information as electrical signals to the control unit. The signals range from simple voltages to complex digital messages on the CAN or LIN bus.
Actuators are the executing elements. They convert control commands into mechanical, electrical or hydraulic movement - for example in the EGR valve, throttle valve actuator or air-conditioning system. They are controlled by the control unit, usually via PWM signals or direct power supply.
Perfect interaction - and how to recognise it
NOx sensor and EGR valve, wheel speed sensor and ABS valve or temperature sensor and air conditioning flap actuator: Whatever the function, sensors and actuators always work as a team. If an incorrect value is recorded or a movement is not carried out correctly, the entire system may be disrupted.
For your workshop customers this means: To perform a diagnosis properly, both sides must be considered - input signals and reaction. Experience is what counts here. Anyone who knows how the systems interact will not only find the fault, but also its cause.
Sensor or actuator? - Narrow down the sources of error
Diagnostics usually begins with the fault memory - but that’s just the start. Live data, multimeters or oscilloscopes help check values and verify the plausibility of signals from the sensors. Frequent causes are cable breakages, contact problems or soiling.
With actuators, the focus is on the function: Can the component be controlled via the actuator test? Are there mechanical or electrical faults? Voltage measurement, visual inspection and - if necessary - calibration after replacement are all part of the day-to-day work in this area.
Avoid flawed thought processes - recognise correlations
Careful logical diagnosis - step by step
• Read out error memory: Is the sensor or actuator affected?
- Carry out a visual inspection - important for every workshop: The cause of the failure may not be at the location of the visible fault.
If a sensor signal value is absent, the actuator may not work even though it is in perfect working order. Or a sensor may report values that seem implausible, but only because the mechanism is blocked.
Therefore: Sensors deliver the information - actuators perform the actions. For a control system to work, there must be interaction between these two sides.
- Check electrical plug connections and cabling
- Check live data: Is the input signal correct? Are there any feedback messages/signals?
• Perform an actuator test: Does the actuator react as expected?
• Measure voltages and signals: Ensure supply and control.
• Check the mechanical system: Look for blockages, wear or jamming.
- Do not forget calibration: This is often necessary after replacement or repair.
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Conclusion: Expertise makes all the difference
Sensors and actuators are the vehicle's sensory and muscular systems. Workshops that have a firm grasp of both areas can diagnose faults reliably - and save time and money in the process. For you as a wholesaler this means: With the right product range and the right expertise, you can give your customers optimum support.
HELLA provides support - with expertise, technology and tools
Whether sensor or actuator: HELLA offers practical diagnostic solutions, technical data, training and support. This enables you to provide your workshops with the right information, spare parts and tools at all times - and make them even more efficient.