Marvel Ice Maker Error Code 4 blinks

The 4 blinks code means that both the bin thermistor and the evaporator thermistor are reading outside their acceptable resistance ranges at the same time. The control board uses these two sensors to monitor storage bin temperature and evaporator plate temperature during ice production. Because neither sensor is returning a valid signal, the unit halts operation and displays this fault. Diagnosis involves resistance testing both thermistors and comparing results to the values in Table C of Section 5.2.

No, you should not attempt to run the ice maker while this fault is active. With both temperature sensors out of range, the control board cannot accurately monitor the evaporator or bin temperatures, which means the unit cannot regulate freeze cycles properly. Continuing to operate it in this state risks damage to the compressor or refrigeration components.

A power reset may temporarily clear the fault display, but the 4 blinks code will return if the underlying sensor or wiring issue is not corrected. Because the code is triggered by actual out-of-range resistance readings from both thermistors, the control board will re-detect the problem as soon as it runs its sensor checks after restart. A proper repair addressing the defective components is required to permanently clear the fault.

A knowledgeable DIYer with a multimeter can perform the initial resistance tests on both thermistors by disconnecting them and comparing readings to the temperature-resistance table in the service documentation. If a thermistor tests out of specification, replacing it is a straightforward task in most Marvel models. However, if the fault points to the control board or a wiring harness problem, professional repair is recommended to avoid further damage.

Repair costs depend on the root cause. Thermistor replacement parts typically range from $15 to $60 per sensor, with labor adding $75 to $150 depending on your service provider. If the control board is at fault, board replacement can bring the total repair cost to $200 to $450 or more. Getting a diagnostic visit first is the best way to estimate the final cost accurately.