Bosch · Dryer
Bosch Dryer E05 Error Code
Main control board relay fault
What this error means
E05 is grouped with Bosch electronic fault codes indicating a relay or driver failure on the main control board. The drum may not start, heat may not engage, or the display may flash E05 at power-up after a surge.
How E05 is detected
When E05 appears on a Bosch dryer, the control board has confirmed that water did not leave the machine within the programmed drain window. On Bosch WTG86401UC, Bosch WQB245AXUC, and similar variants, the drain pump runs for a fixed interval—often three to seven minutes on washers and dishwashers—while a pressure switch or turbidity sensor verifies the tub or sump is empty. If water remains, the cycle stops to prevent spin with a full tub or overflow on the next fill.
Most E05 calls are resolved without parts: turn off the dryer breaker for thirty seconds, then restore power. Restricted drain paths mimic pump failure because the impeller spins against a blocked hose or filter. Document whether the pump hums audibly during the drain step; a humming pump with no water movement points to a clogged filter or kinked hose, while silence may indicate a failed pump motor or loose wiring at the harness.
After clearing blockages, run a short cycle and listen at the drain hose for steady water flow. If E05 returns on the next load with a clean filter and straight hose, measure resistance at the pump motor connector per the service manual for your model before ordering a replacement pump assembly.
Common causes
- Power surge through the laundry circuit during a storm
- Relay welded after prior overheating from blocked airflow
- Loose neutral at the dryer terminal block causing erratic board voltage
- Control board moisture after condensate leak in the base
Step-by-step fixes
- 1Turn off the dryer breaker for thirty seconds, then restore power
- 2Verify the cord or junction connections are tight and the outlet delivers stable 240V on electric models
- 3Run one empty timed cycle after reset before loading clothes
- 4Stop using the dryer if E05 returns at startup without any cycle run
When to call a technician
Bosch lists E05-class faults as technician-only—board relay testing and replacement require authorized service.
Affected models
- Bosch WTG86401UC
- Bosch WQB245AXUC
- Bosch WTG865H4UC
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use dryers to prevent E05 from lint and food debris buildup.
- Record when E05 appears in the cycle and whether it clears after a 60-second power reset on your Bosch dryer—that detail speeds diagnosis if you call service.
- Keep the model and serial number from the rating plate when ordering parts for E05; Bosch uses multiple revisions with different harness lengths and board firmware.
- Photograph wiring connector orientation before disconnecting any component while troubleshooting E05; reversed plugs on pumps and valves cause immediate repeat faults.