Viking ice maker displays E4 and shuts down; ice slab may be too thick or too thin

Safety first: Disconnect power and turn off the water supply before servicing. Hot surfaces and sharp edges are present around the evaporator and tubing.

• Step 1 – Inspect ice thickness probe: Locate the thickness sensor (often a metal or plastic probe near the bottom of the evaporator plate). Ensure it is not bent, broken, or coated with mineral scale.
• Step 2 – Clean evaporator and probe: Use a manufacturer-approved ice machine cleaner. Mix per instructions, run a cleaning cycle if available, or manually circulate cleaner over the evaporator. Rinse thoroughly with clean water to remove all chemical residue.
• Step 3 – Check adjustment: Some Viking models allow mechanical or electronic adjustment of ice thickness. Verify the setting is within the recommended range in the service manual.
• Step 4 – Inspect harvest components: Check the hot gas valve coil and harvest solenoid (if used) for secure wiring and proper operation. With power on and during harvest, you should feel the valve energize. Replace the valve coil if it is open or not energizing.
• Step 5 – Replace thickness sensor if defective: If the sensor is physically damaged or tests out of spec, install a new ice thickness probe or sensor assembly and reconnect to the control board.

After cleaning and adjustments, restore power, clear the E4 code, and observe at least one full freeze/harvest cycle to confirm proper slab thickness and reliable harvest.