Monogram ZBD9900 Dishwasher Code AUTO + SPEED Lights Flashing: turbidity sensor reading uncertain
On a Monogram ZBD9900 top-control dishwasher, such as the ZBD9900RII, the AUTO and SPEED lights flashing together point to the turbidity sensor in the technician's service test. When the control is unsure what that sensor reads,…
- Code
- AUTO + SPEED Lights Flashing
- Appliance
- Dishwasher
- Brand
- Monogram
- Warranty
- 30-day workmanship
What AUTO + SPEED Lights Flashing means
On a Monogram ZBD9900 top-control dishwasher, such as the ZBD9900RII, the AUTO and SPEED lights flashing together point to the turbidity sensor in the technician's service test. When the control is unsure what that sensor reads, the Auto program assumes the water is very dirty. The owner does not see a message, only an Auto cycle that may run longer or use more water than expected. This reading is confirmed for the ZBD9900 series, not for other Monogram models.
Common causes of AUTO + SPEED Lights Flashing
- Turbidity sensor lens covered with film
- Filters and sump holding debris
- Drain system slow to clear water
- Wiring between the sensor and control
1. Lift out the bottom filter and rinse off any film. 2. Wipe any film or residue from the tub walls and the sump area. 3. Run an Auto cycle with a normal load and note its length. 4. Make sure the drain is clear and the hose is not kinked. 5. Call us if the Auto cycle keeps running long.
- The owner can clean the filter, but the sensor sits inside the water path
- We check the sensor, its wiring and the drain behavior
- We separate a dirty lens from a sensor that has stopped working
Other Dishwasher codes
Does the dishwasher still clean?
Yes. In doubt, the Auto program treats the water as dirty, so it errs on the long and thorough side. You may see more water use and longer cycles.
Why only the Auto cycle?
The turbidity sensor is what Auto uses to judge how dirty the water is. Other cycles follow fixed times, so they run as usual. That is why only this cycle behaves differently.
Is it the sensor or the water?
Hard water film and food residue can cloud the sensor. We check the water and the filters first, then the sensor circuit. The answer decides whether a cleaning or a part is needed.
Still seeing AUTO + SPEED Lights Flashing?
A technician diagnoses it on site and gives you the price in writing before any work starts.