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Error code reference
Sub-Zero Refrigerator Error Code 40 8 40
Ice maker ran for maximum fill time without achieving necessary volume.
SourceSub-Zero Service Manual: ICBBI-42UFDID: Service Manualp. 157
Diagnostic procedure
The full 40 8 40 procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Check for water system blockages, kinked water lines, and proper water pressure.
SourceSub-Zero Service Manual: ICBBI-42UFDID: Service Manualp. 157
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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