Bosch dishwashers are among the best-built machines in a domestic kitchen and they generate a predictable set of calls. Two error codes and one non-fault account for most of them.
E24 — it cannot drain
E24 means the machine did not empty in the time it expected. On a Bosch this is an obstruction rather than a pump failure the overwhelming majority of the time.
Work through it in order:
- The filter assembly in the sump. It unscrews by hand. It is designed to be cleaned regularly and most people have never touched it. A clogged filter recirculates the debris it just captured and eventually blocks the drain path.
- The drain hose, for a kink behind the machine. Also check it has a high loop — without one the machine siphons.
- The air gap, if the installation has one on the counter. They fill with debris and nobody looks at them.
- The waste connection. If the dishwasher drains into a disposer, check the knockout plug was actually removed when it was installed. We still find installations where it was not, years later.
In a Chicago two-flat or converted building, add one more: check whether the kitchen sink drains normally and whether the unit above or below has the same complaint. A dishwasher pumping into a partially scaled original stack will throw E24 while everything else behaves.
E15 — the base tray has water in it
E15 means the float in the base tray has lifted, so the machine has shut off its inlet valve to prevent a flood. That is a safety system working correctly. There is water where there should not be.
You can sometimes clear it temporarily: tilt the machine back about 45 degrees to drain the tray, stand it up, and run a cycle. If E15 stays away permanently, it was condensation or a one-off spill.
If it comes back, there is a leak, and finding it is the job. Common sources are the door seal, the pump seal, a hose connection, or the spray arm bearing. Leaving E15 unresolved is how a slow seep becomes a damaged cabinet base and, in a flat building, somebody else's ceiling.
The damp-plastics complaint that is not a fault
This is the single most common Bosch "problem" we are called about, and it is the design.
Bosch dishwashers use condensation drying. There is no exposed heating element in the tub. The machine relies on the residual heat of the load and the cool stainless steel walls to condense moisture out of the air. It is quieter, it uses less energy, and it will not melt a plastic container that has slipped onto the bottom rack.
What it will not do is bake plastics dry. Plastics have too little thermal mass to hold heat, so they stay wet while the china and glass come out dry. That is normal on every condensation-drying machine ever made.
Two things genuinely help:
- •Keep rinse aid topped up. It changes how water sheets off surfaces, and it is most of the drying performance on these machines.
- •Crack the door open at the end of the cycle and give it ten minutes.
The setting the installer skipped
Bosch dishwashers have a configurable water-hardness parameter in the service menu. It tells the machine how to dose and, on models with a softener, how often to regenerate.
Installers routinely leave it at the factory default. Against Chicago's moderately hard Lake Michigan supply the wrong setting produces exactly the film on glassware and spotting that people assume is a failing machine.
We set it correctly during a visit at no extra cost on models that support it. It resolves the complaint without a part more often than you would expect.
What we check on a Bosch call
The water path in the order it flows — supply, heat, circulation, drain — because a complaint about one stage almost always originates in another. Bosch sits on its own European engineering, so procedures are specific to the platform rather than carried over from a wider family, and parts availability is generally good.
The model number is on the edge of the door, visible when the door is open. Send a photo when you book.
Worth repairing?
Almost always. These machines are built to last and most of what fails on them — filters, pumps, valves, seals, hoses — is inexpensive and available. The exception is a control board on a machine well past a decade of use. Integrated and panel-ready installations, which are common in Chicago rehabs, move the threshold further toward repair again, because replacing one means cabinetry work.