Panasonic NR-BN31EX2 Service Manual page 16

7.15. Self Diagnosis Code
Error code is displayed on fridge or freezer temperature display when failure causes.
[E0] and [E1] are displayed on the fridge temperature display.
[E3] is displayed on the freezer temperature display.
7.16. Measuring Points on Main PCB Box
Note: For more detail, refer to the Schematic Diagram on page 38.
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