Carrier · Furnace

45.3 Control failure - EEPROM memory

High severity 59SC6A

What the control is telling you

The control has an internal EEPROM memory problem.

Applies to: Carrier 59SC6A

Likely causes

Control memory failure

Test and repair steps

Cycle power to the furnace.
If code 45 returns, replace the control.
Before handling the board, discharge static by touching grounded furnace metal.
Program the new control with the Model Program Number on the rating plate (mobile app via NFC with 115-V removed, or the correct super plug); never use a different program number.
Confirm program and software in the inF menu, re-enter installer settings, and run a full cycle.

Settings for these units

Filter sizes by casing width and filter cabinet · 59SC6A
Minimum clearances to combustibles · 59SC6A

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Source: Carrier 59SC6A Installation, Start-up, Operating and Service Instructions, Fig. 60 Service Label Information, p.54. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.