E39
Bosch Dishwasher
Severity: ModerateWhat Does This Error Mean?
The E39 error on a Bosch dishwasher indicates a problem detected by the pressure sensor — either the sensor is faulty or it is reading water levels outside the expected range. This sensor monitors how much water is in the tub and helps control the fill and drain cycles. A blocked sensor or actual water level problem can trigger E39.
Affected Models
- SHPM88Z75N
- SHPM65Z55N
- SHEM63W55N
- SHDX5EM3N
- Most Bosch 500, 800 series dishwashers
Common Causes
- Pressure sensor hose is blocked with limescale or food residue
- Pressure sensor itself has failed and needs replacement
- Too much detergent creating excess suds that give false pressure readings
- Wiring to the pressure sensor is loose or damaged
- Actual water level issue — either too much or too little water in the tub
How to Fix It
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Run an empty cycle with a dishwasher descaler or citric acid powder.
Limescale buildup is a very common cause of pressure sensor errors in Bosch dishwashers. Descaling often clears E39 without any parts replacement.
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Make sure you are using the correct amount of dishwasher detergent.
Too much detergent produces excessive suds that can fool the pressure sensor into thinking the tub is overfull. Use only the recommended amount.
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Check that the dishwasher salt reservoir is filled.
Bosch dishwashers have a built-in water softener that uses dishwasher salt. If the salt runs out, hard water deposits build up faster, including on the pressure sensor.
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Reset the dishwasher by unplugging it or turning off the circuit breaker for 5 minutes.
A power reset allows the control board to re-read the sensor. This clears temporary faults.
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If E39 returns, the pressure sensor or its hose needs professional inspection.
A technician can access the sensor from beneath the dishwasher and test it with a multimeter.
When to Call a Professional
If descaling and cleaning the sensor hose does not clear E39, the pressure sensor needs testing. Replacing the sensor requires accessing the bottom of the dishwasher. Expect repair costs of $80–$180.
Frequently Asked Questions
What does the pressure sensor do in a Bosch dishwasher?
The pressure sensor monitors how much water is in the tub at any point during the cycle. It tells the control board when the tub has been filled to the correct level and when it has been drained. If it gives wrong readings, the dishwasher either overfills, underfills, or cannot complete the cycle.
Does dishwasher salt prevent pressure sensor problems?
Yes — Bosch dishwashers use dishwasher salt to soften water before it enters the machine. Softened water leaves far less limescale on internal components, including the pressure sensor. Keeping the salt reservoir filled is one of the most effective ways to prevent sensor errors.
Is E39 a common error on Bosch dishwashers?
It is more common in hard water areas where limescale builds up quickly. With regular use of dishwasher salt and occasional descaling cycles, E39 can usually be prevented entirely. Bosch dishwashers are well-engineered machines — most E39 errors are maintenance-related, not hardware failures.