2019-2021 GMC Sierra 1500 Auto Start Stop Memory Module | Plug & Play

Fits the 2019–2021 GMC Sierra 1500. The plug-and-play memory harness remembers the position of the stop-start button between drives, so the engine no longer shuts off at the first red light after every restart unless you want it to. It plugs in line with the factory connector named in the instructions, using factory-style plugs on both ends, so nothing is cut or spliced.

It does not delete the feature. Turning stop-start back on is the same button press as before, and the module will remember that too. Removing it returns the vehicle to its original default.

Fitment

The fitment table for this SKU lists the following, each marked as a 100% fitment match:

• GMC Sierra 1500: 2019–2021

For reference, the GMC Sierra 1500 in these years is a full-size pickup offered with 2.7L turbo four-cylinder, 4.3L V6, 5.3L V8, 6.2L V8 and 3.0L Duramax turbo-diesel engines. The listing is written around the fifth-generation (2019-up) Sierra 1500. Trim levels are not split out in the table, so confirm that your vehicle has the stop-start button before ordering.

What the factory system does

With Auto Stop/Start active, the engine shuts off when the vehicle comes to a stop and restarts when you lift off the brake or press the accelerator. The off button is a manual override for that drive only. Turn the ignition off and back on, and the system defaults to on again, so drivers who prefer it off end up pressing the button at the start of every trip.

Day-to-day use

Drivers usually switch stop-start off for comfort or habit. A restart at every stop is noticeable in a full-size pickup, the climate system may run at reduced output while the engine is off, and quick moves into traffic feel slower when the engine has to fire first. If those are your reasons, you probably press the button on every drive now. With the module, you press it once.

When the engine will not auto-stop anyway

The factory system will skip an auto stop for many reasons: battery charge below its threshold, cold coolant, high climate-control load, a steep grade, the hood or driver door open, or a 4WD or tow mode on vehicles that have them. Those checks stay in control after this module is installed. It does not force stops and it does not bypass any of those safety inputs.

What the module does and does not do

• 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 remembers the last stop-start setting through a key cycle.
• It does not change engine power, transmission shifts, emissions calibration or fuel trims.

Diagnostics first

A warning light that appears after installation usually means a connector is not fully seated. Switch the ignition off, reseat both ends until the locks click, and test again. If the light stays on, remove the module and confirm the vehicle is fault-free on its own before contacting support.

Installation and removal

It plugs in line with the factory connector named in the instructions, using factory-style plugs on both ends, so nothing is cut or spliced. Work with the ignition off. Seat each connector until its lock engages, then secure the module with the supplied ties or tape so it cannot rattle or touch pedals, steering parts or anything hot. Start the vehicle, press the stop-start button once, then restart to confirm the choice is held.

Battery notes for stop-start vehicles

Most stop-start systems watch battery condition closely through a sensor on the negative terminal. When the battery ages, the system quietly stops auto-stopping long before the battery fails to crank. Keeping the original battery type (AGM or EFB) and a clean, tight ground connection avoids a lot of confusion about why the system behaves differently from week to week.

Fitment check

• Model year and model match a row in the table above (2019–2021 GMC Sierra 1500).
• Your GMC Sierra 1500 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.
• No aftermarket remote start, alarm or gateway bypass is wired into the same circuit. If one is, email support before ordering.
• The connector at your install point matches the one in the product photos.
• If you are unsure, send your VIN to support@automotivebypass.com and we will confirm fitment.

Ordering details

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.