my cuisinart grind and brew just flashes 'clean' and won't let me make coffee, i've descaled it already.

Diagnosis

The "CLEAN" indicator on the Cuisinart DGB-900BC is not triggered by a mineral sensor or a flow-meter that detects scale buildup. Instead, it is a hard-coded cycle counter. Once the machine reaches a specific number of brew cycles (typically every 60-100 pots), the internal logic board triggers the alert to ensure the user maintains the heating element. Because it is a timer and not a sensor, simply running a descaling solution through the machine does not "tell" the computer that the task is complete. The flashing light acts as a soft-lock. While it may allow some functions, it often prevents the start of a new brew cycle to force the user to perform the maintenance sequence. If you have already descaled the machine but the light is still flashing, it is because the specific "Clean" command sequence was not initiated and completed, leaving the internal counter stuck at the alert threshold.

How to Fix It

To clear the "CLEAN" alert and reset the internal brew counter, you must execute the specific cleaning mode sequence. Follow these exact steps:

1. Empty the water reservoir completely and ensure the filter basket is clear of old grounds and paper filters.
2. Fill the water reservoir to the 12-cup maximum line with fresh, cold filtered water. Do not add descaling solution to the reservoir for this reset; use plain water to flush the system.
3. Ensure the carafe is empty and properly seated on the warming plate.
4. Press and hold the "CLEAN" button for 3 seconds. You will hear a beep, and the "CLEAN" light will begin to flash rapidly, indicating the machine has entered the specialized cleaning mode.
5. Press the "BREW" button to start the cycle. The machine will now run a high-temperature flush. This process takes longer than a standard brew cycle because it pulses the water to break up remaining residue.
6. Allow the entire 12-cup reservoir to empty through the system. Do not interrupt the power or open the lid during this process.
7. Once the cycle finishes and the machine beeps, the "CLEAN" light will turn off and the internal counter will reset to zero.

If That Didn't Work

• Hard Power Reset: If the button is unresponsive, unplug the unit from the wall outlet for exactly 10 minutes. This drains the capacitors on the control board. Plug it back in and immediately attempt the 3-second hold on the "CLEAN" button before pressing any other keys.
• Button Contact Failure: On the DGB-900BC, the tactile switches behind the plastic buttons can wear out or collect coffee oils. If the "CLEAN" button doesn't seem to "click" or register, use a cotton swab dipped in 90% isopropyl alcohol to clean around the edges of the button, pressing it repeatedly to work the alcohol into the switch.
• Sensor Misalignment: Ensure the carafe is perfectly centered on the warming plate. If the carafe detection switch is not fully engaged, the machine may refuse to enter the cleaning mode as a safety precaution to prevent water from overflowing the counter.
• Residual Scale Blockage: If the machine starts the clean cycle but stops halfway, a piece of scale may be blocking the showerhead. Use a needle or a small paperclip to poke through the small holes in the spray head at the top of the machine to ensure water flow is not restricted, which can cause the cycle to time out and the light to return.

Heads Up

• Avoid Excessive Vinegar: While white vinegar is popular, frequent use can degrade the rubber gaskets in the DGB-900BC. Switch to a citric-acid-based commercial descaler every third cleaning for better longevity.
• Grinder Maintenance: Every time you run a "CLEAN" cycle, take the opportunity to remove the bean hopper and vacuum out the grinding chamber. Accumulated oils in the burrs can cause the motor to strain and overheat.
• Water Quality: If you live in a hard-water area, the "CLEAN" light will be a suggestion, not a guideline. Perform a manual descale every 30 days regardless of whether the light is flashing to prevent the heating element from burning out.
• Carafe Positioning: Always ensure the lid of the carafe is closed during the cleaning cycle; some versions of the DGB-900BC have a drip-stop valve that requires specific pressure to flow correctly.