2016-2019 Cadillac CTS Auto Start Stop Eliminator

Built for the 2016–2019 Cadillac CTS, 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.

Which Cadillac CTS models it fits

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

• Cadillac CTS: 2016–2019

For reference, the Cadillac CTS in these years is a midsize sport sedan offered with 2.0L turbo four-cylinder and 3.6L V6 engines, most of the driving it sees is daily commuting, ride-share duty and highway travel. The listing is written around the third-generation (2014-2019) CTS. Trim is not listed separately. Any trim in these years with factory stop-start and the pictured connector is covered.

How Auto Stop/Start behaves from the factory

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.

Battery notes for stop-start vehicles

Vehicles with stop-start normally use an AGM or EFB battery sized for repeated restarts. If you replace it, use the same type and size, and follow the manufacturer's battery reset or registration step where one exists. A wrong or unregistered battery can leave the stop-start system disabled, and that has nothing to do with this module.

What changes after installation

• Does not disable warning lights or diagnostic functions.
• Comes out in the same way it went in, with nothing cut.
• Fuel use changes only the way it would if you pressed the off button yourself.
• Carries your stop-start choice over to the next drive.

Installing the inline memory harness

It plugs in line with the factory connector named in the instructions. Both ends are factory-style plugs, so nothing is cut or spliced. The instructions show the connector for this application; compare it with the product photos before starting. Turn the vehicle off, make the connection, fix the module in place, and test with two or three key cycles.

If something does not look right

If a "stop-start unavailable" or similar message appears, check the battery first. A battery that tests weak, a recent battery replacement that was not registered where the manufacturer requires it, or a fault in the battery current sensor can all disable the system. Clear up those issues before judging how the module works, because it cannot hold a setting the vehicle refuses to accept.

Where owners notice the difference

Drivers usually switch stop-start off for comfort or habit. A restart at every stop is noticeable in a midsize sport sedan, 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

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.

Check before you order

• Model year and model match a row in the table above (2016–2019 Cadillac CTS).
• Your Cadillac CTS has the factory stop-start button. Base trims or engines without stop-start have nothing for the module to remember.
• 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.
• The battery and charging system test good and no warning lights are on.
• If you are unsure, send your VIN to support@automotivebypass.com and we will confirm fitment.

Shipping, returns and warranty

We ship free within the contiguous United States (1–2 business days to dispatch, roughly 3–4 business days in transit). If it turns out to be the wrong part, request a return authorization within 45 days; returns carry a 20% restocking fee and return postage is on the buyer. Coverage is a 3-year limited warranty. Questions go to support@automotivebypass.com, weekdays 9 a.m. to 5 p.m. PST.