2016-2018 Cadillac CT6 Auto Start Stop Eliminator

Built for the 2016–2018 Cadillac CT6, this inline memory harness keeps Auto Stop/Start in whatever state you left it. Press the button once, and the setting carries over to the next start. It plugs in line with the factory connector named in the instructions. Both ends are factory-style plugs, so nothing is cut or spliced.

Nothing is reprogrammed in the engine computer. The module only stands in for the button press you would otherwise make after every start, and it comes out without leaving a trace.

Covered model years

Listed applications (each row is a 100% fitment match for the factory connector this part uses):

• Cadillac CT6: 2016–2018

For reference, the Cadillac CT6 in these years is a full-size luxury sedan offered with 2.0L turbo four-cylinder, 3.6L V6 and 3.0L twin-turbo V6 engines, most of the driving it sees is daily commuting, ride-share duty and highway travel. Trim is not listed separately. Any trim in these years with factory stop-start and the pictured connector is covered.

What the factory system does

Auto Stop/Start 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 changes after installation

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

Where owners notice the difference

Stop-start saves the most fuel in long idles, but plenty of drivers would rather keep the engine running. Common reasons: towing or hauling, where an engine restart under load is unwelcome; drive-thru lines and parking lots, where the engine cycles on and off every few feet; hot days, when the A/C compressor stops with the engine on many vehicles; and stop-and-go traffic where the restart delay is noticeable when pulling into a gap. On a full-size luxury sedan, any of these can mean a button press at the start of nearly every drive.

Diagnostics first

If the setting is not remembered, check that the module was installed with the ignition off and that the connector clicked into place. Then press the factory button once, switch the vehicle off, close the doors, give the electronics time to shut down, and start again. If it still resets, contact support with the year, trim and a photo of the connector.

Keep the battery healthy

If the stop-start indicator shows the system as unavailable, test the battery before anything else. On stop-start vehicles that is the most common cause. A replacement should match the original specification (AGM or EFB), and some manufacturers call for a battery monitor reset after the swap.

Installation and removal

It plugs in line with the factory connector named in the instructions. Both ends are factory-style plugs, 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.

Things that already block an auto stop

Even with Auto Stop/Start enabled, the engine control logic only stops the engine when conditions allow it. Typical blockers are a low battery state of charge, an engine that has not reached operating temperature, heavy heating or A/C demand, steering input, an open door or unlatched seatbelt, and some drive modes. If the system never seems to stop the engine, one of these is usually the reason, and the module does not change that logic.

Confirm these points

• Model year and model match a row in the table above (2016–2018 Cadillac CT6).
• Your Cadillac CT6 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

Standard shipping inside the lower 48 states costs nothing; allow 1–2 business days of handling plus 3–4 in transit. Returns need approval first and must be requested within 45 days. Approved returns are subject to a 20% restocking fee, with return shipping paid by the customer. A 3-year limited warranty applies. Email support@automotivebypass.com (Mon–Fri, 9–5 PST) with your VIN if you want a fitment check.