R-Pro › Field cases › Components
EEV Stepper Motor Coil Open Circuit — Resistance Test 40–80Ω
Likely causes
Coil winding internal open circuit — vibration, overcurrent, or deterioration
Check: Measure coil resistance with multimeter (connector disconnected): A1-A2 and B1-B2 each 40–80Ω; OL confirms open circuit
What to do: If model allows separate coil replacement → replace coil only; otherwise → replace full EEV → run Reset/Initialize on controller after replacement
Connector pin corrosion or increased contact resistance
Check: If coil resistance is normal (40–80Ω) → connector pin pull test + contact resistance below 2Ω
What to do: Clean contacts with pin cleaner, re-measure contact resistance → if no improvement, replace connector
EEV driver board output stage failure
Check: Coil resistance normal + connector normal → check EEV driver board for 5V control signal output with oscilloscope
What to do: Check supply voltage and controller comms line before replacing driver board → initialize EEV after board replacement
Always measure coil resistance with connector disconnected — measuring while connected to driver board gives false readings
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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