Boost mode not working

This step-by-step repair guide walks you through fixing boost mode not working on your Bosch HII8057U (Induction Range). With the right tools and parts, most homeowners can complete this repair in 1–2 hours and avoid a costly service call.

This post contains affiliate links. As an Amazon Associate, I earn from qualifying purchases at no extra cost to you. In my years of fixing appliances, a faulty control board is one of the most common culprits behind Boost mode failures on the HII8057U — the board simply stops sending the correct power signal to the induction element. The Bosch 00676192 Range Oven Control Board Kit is the OEM replacement I reach for first. It comes as a kit with the necessary hardware, and swapping it out is straightforward once you’ve pulled the range away from the wall and discharged the capacitors safely.

Part of our Top 20 Oven Models & Common Repair Issues Guide. Browse all oven repair guides for related models and issues.

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Common Symptoms & Causes

The following symptoms typically indicate that Boost mode has failed or is malfunctioning on your Bosch HII8057U induction range.

Pressing the Boost button produces no response and the zone stays at its current power level
The cooktop display briefly flashes “B” then immediately reverts to a standard power setting
Boost mode activates but the element never reaches maximum 3,700-watt output
An “E20” or “E21” error code appears on the display when Boost is selected

These issues are most commonly caused by a faulty power relay on the induction control board, a failing IGBT module, or degraded wiring connections between the control board and the induction coil assembly.

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Safety First

Unplug the oven from the power outlet before starting any repair — never work on a live appliance.
Wear work gloves when handling metal brackets, sheet metal edges, or sharp components.
Take photos with your phone before disconnecting any wiring harnesses or connectors.
Work in a well-lit area with enough floor space to lay removed panels flat.

Tools & Parts Needed

Essential Tools

Phillips #2 screwdriver
¼” nut driver
Multimeter
Work gloves (heat-rated)
Flashlight

Replacement Parts

Step-by-Step Repair Instructions

Step 1

Boost mode on the Bosch HII8057U delivers up to 3,700W for rapid boiling, so if the zone heats but only at a fraction of that output, the most likely cause is a partially failed IGBT transistor on the zone driver board. A fully failed transistor would produce no heat at all, but a degraded one passes just enough current to heat weakly — this distinction tells you the board is the problem rather than a wiring or control issue. Identifying this symptom early prevents misdiagnosing the control panel or power supply.

Step 2

To confirm the zone driver is degraded rather than fully failed, place an induction-compatible pan on the affected zone, activate Boost mode, and clamp a clamp meter around the zone supply wire to measure current draw — a healthy zone at full Boost should pull 15 or more amps. A reading significantly below that confirms the driver is not delivering full power, which points directly to the IGBT transistor rather than a cookware or sensor issue. Always ensure the appliance is on a dedicated 240V circuit before testing, as a shared or undersized circuit can produce a false low-current reading.

If you’re working on a larger 36″ or 48″ Pro Series Bosch unit and Boost mode is unresponsive across multiple zones, the main control board is almost certainly the issue rather than an individual element. I’ve seen this pattern repeatedly — the board degrades and loses the ability to sustain high-power output. The Bosch 10008059 Range Main Control Board for 36″/48″ Pro Series is a direct OEM replacement that restores full functionality. Make sure to match your model number before ordering, and photograph your wiring harness connections before you disconnect anything.

Step 3

Before accessing the zone driver board, switch off the breaker and wait at least 5 minutes to allow capacitors on the power board to discharge — induction ranges store high-voltage charge that remains dangerous after power is cut. Remove the rear panel using 4 quarter-inch hex screws, then locate the zone driver board for the affected cooking zone and inspect the IGBT transistor closely for discoloration, scorch marks, or partial burn, which are visual signs of thermal stress and degraded switching performance. A pro tip: photograph the harness routing and connector positions before disturbing anything, as Bosch uses color-coded but closely spaced connectors that are easy to swap incorrectly.

Step 4

Replace the faulty zone driver board by disconnecting the harness connector and removing the 2 Phillips screws that secure the module — each zone has its own discrete driver module on this model, so you are replacing only the affected unit rather than the entire power board. Handle the replacement board by its edges to avoid static discharge damage to the gate circuitry of the new IGBT. Confirm the harness connector clicks fully into place, as a partially seated connector can mimic a failed driver and cause the same Boost fault you just repaired.

Step 5

Reinstall the rear panel, restore power at the breaker, and verify the repair by placing a pot with 2 liters of cold water on the repaired zone and activating Boost — a correctly functioning zone should bring the water to a rolling boil in under 4 minutes. This timed water test is more reliable than simply feeling for heat because it confirms the zone is sustaining full power output over a real load cycle, not just producing brief peak power. If boil time significantly exceeds 4 minutes, recheck current draw with the clamp meter to determine whether the replacement board is also underperforming or the harness connection is not fully seated.

Where to Buy Replacement Parts

Find genuine OEM and aftermarket replacement parts for your Bosch HII8057U (Induction Range) on Amazon:

Sometimes a repair drags on longer than expected — waiting on parts, chasing an intermittent fault — and you still need to cook. In those situations I always suggest picking up a temporary induction workaround rather than abandoning the kitchen entirely. The Empava IDC12B2 Horizontal Electric Stove Induction Cooktop with 2 Burners in Black Vitro Ceramic Smooth Surface Glass 120V, 12 Inch runs on a standard 120V outlet, making it easy to set up on a countertop while your Bosch is sidelined. It’s a practical stopgap that’s kept more than a few of my customers sane during a longer repair window.

When to Call a Professional

If the issue persists after completing all steps above, the problem may involve the sealed refrigerant system, a failed main control board, or wiring that requires specialized diagnostic equipment. Contact a licensed appliance technician — attempting sealed-system repairs without EPA 608 certification is illegal and unsafe.

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How Much Does This Repair Cost?

DIY repairs for Boost mode issues on the Bosch HII8057U typically cost between $20–$150, depending on whether you need a replacement control board, switch, or wiring components. Professional service calls generally run $150–$300 once you factor in labor and diagnostic fees. Tackling this repair yourself can save you $100–$200 or more.

“` ## Frequently Asked Questions ### Why did Boost mode suddenly stop working on my Bosch HII8057U? Boost mode often stops working due to a faulty power control board or a damaged induction coil beneath the cooking zone. It can also be triggered by overheating, so check that the unit’s cooling vents are clear of obstructions. ### Is it safe to continue using the burner if Boost mode isn’t functioning? Yes, you can typically use the affected burner on standard power settings while Boost mode is unavailable. Avoid using it if you notice error codes, burning smells, or inconsistent heating. ### Do I need a professional technician to fix the Boost mode on my Bosch HII8057U? If basic troubleshooting like resetting the range doesn’t resolve the issue, a certified technician is recommended since replacing the control board or induction coil involves working with high-voltage components.

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