dET and F8 E2 affect the Whirlpool dispenser, but they do not mean the same thing: dET indicates that the cartridge is not detected, and F8 E2 points to a problem in the dispensing system.
dET: check whether a cartridge is being used
On compatible models in the manufacturer documentation, check that the cartridge is inserted into its slot and that the drawer is fully closed. If you are using the manual dispensing supported by that unit, dET may not require correcting a missing cartridge: check the selected mode before adding product.
Do not place a cartridge in a drawer that does not include one, and do not force it to fit. Note whether the alert started after removing it, refilling it, or changing the setting.
F8 E2: residue and dispensing path
Stop the cycle and check which drawer parts the manual allows you to remove. Clean any accessible detergent buildup and reassemble each insert in its position. The guide to automatic dispensing cleaning explains the difference between the reservoir and the circuit.
If the cartridge is recognized but the product is not being used, or F8 E2 reappears with the drawer clean, request a diagnosis. Adding more detergent does not prove the system is dispensing and may end up doubling the dose.
Report separately the message displayed, the dispensing mode, and whether the product is actually being used.