E40
Bosch Dishwasher
Severity: ModerateWhat Does This Error Mean?
The E40 error on a Bosch dishwasher indicates a control board fault — the main control board (also called the PCB or program control unit) has detected an internal error. The board manages all functions of the dishwasher, so when it reports a fault, cycles cannot run correctly.
Affected Models
- SHPM88Z75N
- SHPM65Z55N
- SHEM63W55N
- SHDX5EM3N
- Most Bosch 500, 800 series dishwashers
Common Causes
- Main control board has experienced an internal electronic fault
- Power surge damaged the control board circuitry
- Water leaked onto the control board, causing a short circuit
- Wiring harness connections to the control board are loose or corroded
- Software or firmware error requiring a reset
How to Fix It
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Turn off the dishwasher at the circuit breaker and wait 10 minutes.
A full power reset is always the first step for a control board error. This allows the board to restart completely.
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Restore power and try to start a cycle.
If E40 does not appear immediately, run a complete cycle and monitor. A one-time E40 from a power spike may not return.
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Check for any signs of water around the control board area.
The control board is typically located behind the front door panel. If water has reached it — from a leak inside the door — the board may have shorted.
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Check all wiring harness connections visible at the control board.
Loose or corroded connectors are a common cause of intermittent control board errors. A technician can access these properly.
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If E40 persists on every cycle, the control board needs professional testing and likely replacement.
Do not keep trying to run cycles with a confirmed control board fault — this can cause additional damage.
When to Call a Professional
Control board faults usually require professional diagnosis. A technician needs to confirm whether it is a wiring issue or a failed board before ordering a replacement. Bosch control boards can be expensive — expect $150–$400 for the repair.
Frequently Asked Questions
How much does it cost to replace a Bosch dishwasher control board?
Bosch control boards typically cost $80–$250 for the part. Labor adds $80–$150. Total repair is usually $150–$400. For older dishwashers, compare this cost against a new machine before committing to the repair.
Can a power surge damage a Bosch dishwasher control board?
Yes — dishwasher control boards contain sensitive electronics that are vulnerable to voltage spikes. If you have frequent power fluctuations, consider plugging the dishwasher into a surge-protected outlet. Most dishwashers are hardwired, so a whole-house surge protector installed at the breaker panel is the best option.
Is E40 always a control board failure?
Not always — sometimes E40 is caused by a loose wiring connector or a temporary software glitch. A reset and wiring check should always come before replacing the board. However, if it returns consistently, the board has likely failed and needs replacement.