Bosch Dishwasher Service Test Result 1: Aqua Sensor

What 1 means

Run the service test program on an older Bosch dishwasher with a two-digit display and it reports what failed as a number. A 1 is the Aqua Sensor, Bosch's optical turbidity sensor, sold as Sensotronic in that generation. When several problems exist the numbers are summed, so seeing 3 means the sensor plus the heating system. Cleaning often settles this one before any part is ordered.

Common causes of 1

Greasy or scaly film across the sensor window
Sensor dead or its cable damaged
Sensor left out after earlier work

✓ One safe check you can try

1. Unplug the machine. 2. Remove the filters and wipe the sump clean, including the area around the sensor window. 3. Reinstall the filters. 4. Run an empty hot program with a dishwasher cleaner, then run the test again before deciding the part has failed.

! Why to stop there

Test numbers add together, so a wrong reading can send you after the wrong part.
A coating on the window looks like a dead sensor.
Handling the sensor wiring without power off risks damage.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Dishwasher codes

E:01Bosch Dishwasher E:01: Cycle Ended Early, Heater Relay or Pump Unconfirmed E:30Bosch Dishwasher E:30, Voltage Too High and the Machine Shut Down E:31Water in the Zeolite Container - Bosch Dishwasher E:31 FBosch Dishwasher F on an Older Display (Water Filling) 2HBosch Dishwasher 2H: Long Cycle Warning on Older Displays 2Bosch Dishwasher Service Test Result 2: Heating Group 4Bosch Dishwasher Service Test Result 4: Water Filling 8Bosch Dishwasher Service Test Result 8: Temperature Sensor

11 questions

What does adding numbers mean on the test program?

If several problems exist, the display shows their sum. For example, 1 plus 2 shows as 3, so we read the total and work out which problems combine.

Can I run the test program myself?

The procedure is in the service documents, and we run it on every visit. At home, a cleaning of the sump is the useful step; reading and acting on the results is our job.

Is an older dishwasher worth repairing for this?

If cleaning does not clear it, a sensor is a modest repair. We tell you what we find and give you a written price before any work.