Systematic actuator diagnostics
Systematic actuator diagnostics: Actuator diagnosis separates four evidence channels: ECU command, actuator power/ground, electrical current response and real physical movement/flow/pressure. The page also includes a worked example and measurement sequence.
Technical frame
Systematic actuator diagnostics: Actuator diagnosis separates four evidence channels: ECU command, actuator power/ground, electrical current response and real physical movement/flow/pressure. The page also includes a worked example and measurement sequence.
The technical values here expose the standard, protocol or physical relationship directly; model-specific service values are linked through the matching model/variant dossier.
The goal is not only to define the term but to let the reader calculate and interpret what the data means in a scan, scope or physical test.
Concrete technical facts
- Actuator diagnosis separates four evidence channels: ECU command, actuator power/ground, electrical current response and real physical movement/flow/pressure.
- PWM duty cycle shows command proportion only; it does not prove that the load drew current or produced mechanical output.
- In a solenoid current ramp, slope relates to inductance/supply while peak or plateau can reflect driver current limiting and mechanical motion.
- In H-bridge motor actuators, direction can be reversed by changing voltage polarity across the motor terminals.
- With position feedback, target/actual tracking error can come from supply, mechanical sticking, feedback sensing or calibration.
- Loaded voltage-drop testing is more informative than simply seeing 12 V/24 V open-circuit because connection resistance appears under real current.
Worked example
- Example: with 70% command, 13.8 V supply and 0 A current, investigate open circuit/driver/load first; if current is 4 A but position does not move, mechanical sticking or linkage/gearing becomes more likely.
Measurement and verification sequence
- Record command/duty and target value.
- Measure actuator power/ground under load.
- Capture current waveform with a current clamp.
- Independently verify physical output such as position, pressure or flow.
Fault-separation logic
- Is a valid command present and are power/ground/network healthy?
- Does feedback follow the command?
- Does an independent physical measurement confirm the output?
- Is the fault limited to a specific temperature/load/speed condition?
- Does the result remain stable when the original condition is repeated after repair?
Technical sources
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Model-specific real technical data · Measurement references · Technical diagnostic atlas