Bosch Factory Service ManualFault Code: E20

Bosch Dishwasher Error Code E20: Circulation Wash Motor Electrical Resistance Fault

The main wash circulation motor windings exhibit abnormal resistance or an open circuit, preventing wash water pressurization.

Target Appliance

dishwasher

OEM Certified Technical Diagnostic Tree

Diagnostic Tool Required

Digital Multimeter

Measure Ohms resistance, continuity & line voltage.

Triage Complexity

Advanced Diagnostic

4 Sequential manufacturer inspection branches.

Sequential Factory Diagnostic Tree

Perform each diagnostic step in order. Disconnect electrical power and turn off utility shutoffs before inspecting wiring or internal mechanical assemblies.

Step 1: Physical & Electrical InspectionMultimeter & Visual

Action: Disconnect power, remove right-side panel, and disconnect the main 3-phase motor harness on the wash heat pump.

Bench Test: Measure electrical resistance across all three motor winding terminal pairs with a digital multimeter.

Expected Standard: Balanced resistance of approximately 45 to 55 ohms between all pin pairs (1-2, 2-3, 1-3).

If Failed / Out of Spec:

Unbalanced or open winding (0L). Replace wash motor heat pump (12008381).

If Passed:

Proceed to Step 2.

Step 2: Physical & Electrical InspectionMultimeter & Visual

Action: Inspect motor connector plug and terminals for moisture, corrosion, or burnt pin contacts.

Bench Test: Check plastic connector housing for thermal distortion or green oxidation.

Expected Standard: Pristine gold/tin contacts with zero corrosion.

If Failed / Out of Spec:

Clean contacts or replace wiring connector (00624026).

If Passed:

Proceed to Step 3.

Step 3: Physical & Electrical InspectionMultimeter & Visual

Action: Perform insulation resistance check between each motor winding pin and chassis ground.

Bench Test: Set multimeter to mega-ohms (MΩ) and measure from each motor pin to the stainless tub chassis.

Expected Standard: Greater than 10 MΩ (infinity).

If Failed / Out of Spec:

Motor has shorted to ground. Replace heat pump assembly (12008381).

If Passed:

Proceed to Step 4.

Step 4: Physical & Electrical InspectionMultimeter & Visual

Action: Inspect main power module inverter drive section in rear base.

Bench Test: Inspect motor driver IGBT chips for heat pitting or blown capacitors.

Expected Standard: Clean board traces, zero burnt components.

If Failed / Out of Spec:

Replace main power module (11028637).

If Passed:

Clear control error log via service diagnostic test.

Verified OEM Replacement Parts

Cross-referenced factory part numbers for Bosch dishwasher error code E20. Always replace defective components with authentic OEM parts to maintain UL safety certification.

Component Name	OEM Part Number	Manufacturer	Status
Wash Circulation Heat Pump Motor	`12008381`	Bosch	Direct Fit OEM
Main Electronic Power Control Module	`11028637`	Bosch	Direct Fit OEM
Sump Heat Pump Gasket Hose Kit	`00624026`	Bosch	Direct Fit OEM

Need Local Diagnostic Assistance?

Connect with a Certified Bosch Technician in Your Area

If multimeter testing reveals an internal short, locked motor, or fried control board, let an experienced local technician complete the repair with certified OEM replacement parts.

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Frequently Asked Questions: Bosch E20

What causes Bosch dishwasher error code E20?

The main wash circulation motor windings exhibit abnormal resistance or an open circuit, preventing wash water pressurization.

Can I reset the E20 code by unplugging the dishwasher?

While disconnecting power for 5 minutes may temporarily clear the display control memory, the E20 code will reoccur once the microcontroller detects the mechanical or electrical fault again.

What OEM replacement parts are required for Bosch E20?

Common OEM replacement components include: Wash Circulation Heat Pump Motor (OEM #12008381), Main Electronic Power Control Module (OEM #11028637), Sump Heat Pump Gasket Hose Kit (OEM #00624026).