E4 error appears when trying to start a pressure-cooking program; cooker will not build pressure.

Safety first: Ensure the cooker is cool and fully depressurized before inspecting the lid. Unplug from the outlet.

• Check lid alignment: Open and close the lid several times, making sure it aligns with the body marks and locks with a positive click. Do not force the lid.
• Inspect lid switch actuator: On many Black+Decker pressure multicookers, a small plastic tab on the lid engages a microswitch in the body. Check that this tab is not broken or worn down.
• Clean around the hinge: Food buildup near the hinge or locking ring can prevent the lid from fully closing. Clean with a damp cloth and dry thoroughly.
• Test other modes: Try a non-pressure mode (e.g., Sauté). If E4 only appears on pressure modes, the pressure sensor or lid switch circuit is suspect.
• Advanced check: With the unit unplugged and bottom cover removed, locate the lid switch wiring harness where it connects to the main PCB. Ensure the connector is fully seated and wires are not pinched or broken.