The E24 error code on a Bosch dishwasher means the machine could not confirm that water drained. A clogged filter or blocked air gap can cause it just as easily as a hardware fault. Start with the checks that do not require tools.
What E24 actually means
Bosch uses E24, or a blinking light sequence on some older models, to signal a drain fault. The control board ran the drain step and did not see the expected result. The cause can be a clogged filter, kinked hose, blocked air gap, disposal connection, failed pump, or wiring problem.
It does not automatically mean the pump is broken. Bosch uses E25 for a more pump-specific blocked or failed pump condition. E24 is the broader signal that water did not leave as expected.
Most likely causes, in order
Clogged filter assembly. The cylindrical filter and flat mesh screen collect food debris. When they pack up, water cannot move quickly enough and E24 appears.
Blocked drain hose or air gap. A hose can kink behind the machine. An air gap on the counter can collect grease and food residue and block the outflow.
Disposal knockout still in place. When the drain connects to a garbage disposal, a plastic knockout plug must be removed during installation. A recently replaced disposal is a reason to check this connection.
Drain pump failure. If the filter, hose, air gap, and disposal connection are clear, the pump may be worn or jammed. A hum or grind during the drain step is useful information.
Control board or wiring issue. This is less common. A sensor, harness, or board output can create a false drain fault.
Two safe checks to do yourself
Pull out the bottom rack. Twist the cylindrical filter counterclockwise and lift it out, then lift the flat mesh screen underneath. Rinse both and scrub lightly if needed. Reinstall them securely.
Under the sink, check that the drain hose is not kinked or pinched. If there is an air gap, remove its cap and clear visible debris. Run a short cycle and see whether E24 returns.
If the code comes back after these checks, stop there. The next steps can involve pulling the dishwasher, testing pump voltage, or entering diagnostic mode. Guessing at a pump or control board can cost more than a replacement decision.
What a technician checks
A technician can run the Bosch diagnostic cycle, review fault history, test the drain pump, verify voltage, inspect the impeller and wiring, and check board outputs. That sequence separates a blocked drain path from a failed component.
The honest next step
If the filter, hose, air gap, and disposal connection are clear and E24 remains, this is not a repair we take on. A qualified Bosch appliance technician can provide a repair or replacement recommendation. For premium dishwashers such as Fisher & Paykel, Miele, or Cove, see our dishwasher service information.
For more homeowner-safe troubleshooting guides, visit the Home Service Pros information resource.