Washer does not heat and may stop with E09; often on Bosch i-DOS or high-efficiency models

Safety first: Unplug the washer and ensure no standing water is inside before accessing electronics.

• Visual inspection: Remove the rear panel and inspect the heater and wiring for signs of burning or insulation damage.
• Test heater resistance: Disconnect heater wires and measure resistance. A very low resistance (near short) or visible damage indicates a failed heater that must be replaced.
• Check for earth leakage: Measure resistance between each heater terminal and the metal chassis. Any low resistance indicates a ground fault; replace the heater.
• Inspect power module: Access the power module (usually behind the control panel or at the base). Look for burnt tracks or components near the heater relay. If damaged, the module will need replacement or professional repair.
• Replace faulty parts: Install a new Bosch heater and, if necessary, a new Bosch power module. Reassemble and run a hot wash to confirm proper heating.