2025-2026 Hyundai Tucson Limited ISG Eliminator | Memory Harness

This ISG memory harness is for the 2025–2026 Hyundai Tucson. It stores the last stop-start setting you chose, so if you turned ISG (Idle Stop & Go) off on one drive, it stays off the next time you start the engine. It connects at the ISG button circuit, between the switch and its factory plug.

You can still use the original button at any time. Whatever you select last is what the module repeats on the next start. Take the module out and the vehicle behaves exactly as it did from the factory.

Fitment

This part is listed for these vehicles, all marked 100% fitment match:

• Hyundai Tucson: 2025–2026

The table does not separate trims; what matters is that the vehicle has factory stop-start and the connector shown in the photos.

Why the button resets

ISG (Idle Stop & Go) is designed to default to on. The off switch (usually marked with an "A" inside a circular arrow) cancels it for the current drive. At the next start the system is armed again. That reset is intentional on the manufacturer's side, and it is the only behavior this module changes.

What to expect

• It remembers the last stop-start setting through a key cycle.
• It leaves the factory button working, so you can turn stop-start back on whenever you want.
• It does not write anything to the vehicle's modules, and removing it restores the stock default.
• It does not change engine power, transmission shifts, emissions calibration or fuel trims.

A note on the battery

The module draws its power from the vehicle and does not change charging behavior. If your Hyundai Tucson sits for long periods, the same rules apply as without it: a maintainer helps, and a battery that tests weak should be replaced with the type specified for stop-start vehicles (usually AGM or EFB).

Why owners turn it off

Pressing the same button on every drive is what wears on owners. People who tow, plow, idle in pickup lines, creep through heavy traffic or simply want the engine running at a light end up making the same press dozens of times a week. On the Hyundai Tucson, the module turns that into a one-time choice you can still change whenever you want.

Installing the ISG memory harness

It connects at the ISG button circuit, between the switch and its factory plug. Disconnect nothing else and splice nothing. Once both plugs are locked, tuck the harness where it will not be pinched when the panel goes back on. Test by switching ISG (Idle Stop & Go) off, cycling the ignition and checking the indicator.

Diagnostics first

A dead or weak battery, a charging problem or an unrelated module fault will change how ISG (Idle Stop & Go) behaves with or without this part installed. Scan the vehicle for stored codes, test the battery and confirm the system works normally with the factory button before installation. That baseline makes any later issue easy to pin down.

If stop-start is not engaging

A Hyundai Tucson that rarely auto-stops is often telling you something about the battery. Stop-start vehicles usually run an AGM or EFB battery, and the system is one of the first features to drop out as that battery ages. Cabin temperature requests, engine temperature and brake pressure also factor in. None of these checks are altered by the module.

Fitment check

• Model year and model match a row in the table above (2025–2026 Hyundai Tucson).
• Your Hyundai Tucson has the factory stop-start button. Base trims or engines without stop-start have nothing for the module to remember.
• The battery and charging system test good and no warning lights are on.
• The connector at your install point matches the one in the product photos.
• No aftermarket remote start, alarm or gateway bypass is wired into the same circuit. If one is, email support before ordering.
• If you are unsure, send your VIN to support@automotivebypass.com and we will confirm fitment.

Shipping and support

Shipping is free to the contiguous US. Orders leave in 1–2 business days and usually arrive 3–4 business days later. Returns are accepted within 45 days with pre-approval; a 20% restocking fee applies and the buyer covers return shipping. The part carries a 3-year limited warranty, and support@automotivebypass.com answers Monday to Friday, 9–5 Pacific.