Q: Antitheft system causing car to not start

asked by on February 09, 2016

The passive antitheft system is causing my car to not start.

Depending on where and how the security system was installed, this can change the possibilities of various issues and fixes. An aftermarket system put in by a private party could have been installed in different ways that could cause issues with the starting system or other sources depending on what the power is being drawn from. As where an OEM security system that came with the vehicle will have wiring diagrams and more diagnostic specified information about where the problem is coming from. Also there is a possibility that the dealer installed an aftermarket security system which falls in the middle of the other two. Possibly because the dealer may have had the schematics for the installation or in some cases they may have not. The best plan of action would be to have a qualified technician like the ones here at YourMechanic, perform an electric diagnostic on the security system in order to map out how the siren was installed. If the system wasn’t installed properly the car might not start. In this situation it can only be started with the supplied key fob with an auto start. In some bad cases it’s possible for the vehicle to not shut off at all.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Why when I start my car its very accelerated?

If you are getting a very high idle when you first start the car and it comes down to a normal idle in less than five minutes, then you may have a vacuum leak in the intake manifold gasket that...

Valve cover replacement? 2001 Mitsubishi Montero Sport

Hi there - manufacturers are using plastic for valve covers, intake manifolds, and other engine components more and more often for weight and expense savings. Unfortunately, with repeated heat cycles, some of these plastics become brittle, or warp and won't...

I have a 2002 Ford F-150 single cab has a rod knock and dies while driving

Hi There, The rod knocking you are hearing in your 2002 F150 may be related to a rod bearing that is beginning to fail. Adding additional oil to the motor may temporarily solve this, but it will eventually come back...

My engine dies when idling if I don't give it gas

Hey there, thank you for asking about your 2007 Honda CR-V. This is a common issue on many cars and is often times related to what is called an idle air control module. This module regulates the air flow into...

Car shakes, lights dim, won't accelerate

Shaking or vibrating may be caused by many different things such as faulty spark plugs, poor fuel pressure or misfires. Other things such as a faulty idle air control valve may cause the engine idle to drop below the normal...

Van surges and transmission shifts hard. Driving down the road you can feel the engine kick back. Sometimes will die down and cut

Hey there. The transmission control module (TCM) helps regulate fuel efficiency and power while storing information about the transmission system in its memory. A faulty transmission control module may cause a delay in acceleration or erratic shifting of gears. ...

Cruise control broken

Hi. Cruise control systems only engage past about 35 mph, so make sure that is not the issue. Other issues that can sometimes interfere with the cruise control are brake lights that may be having connection issues. The system uses...

How do I adjust the rearview mirror?

The rearview mirror is an important safety feature that provides you with visibility out your rear window. Before driving, you should always adjust your rearview mirror so that you have maximum visibility. To adjust the mirror, manually move it up,...

My car tries to start by then just turns off. 2005 Ford Freestyle

If the fuel pump is good, but is not pumping fuel then it is usually due to an issue with the inertia fuel cut off switch. This is located under the dash. It is designed to cut fuel off to...

Related articles

A Buyer’s Guide to the 2012 Ford Expedition
The The 2012 Ford Expedition has ample room for passengers and cargo, while still being able to tow anywhere from 8,900 to 9,200 pounds. The Expedition has two-tone exterior packages making it stand out against its competitors. Along with that,...
A Buyer’s Guide to the 2012 Ford Fusion
Choosing Choosing a mid-size sedan for your family can be a tough call. There’s a lot of competition out there, including really popular models like the Honda Accord and Toyota Camry. Among all those, though, the 2012 Ford Fusion really...
The Best Used Cars to Buy If You’re a Caterer
If If you are in the catering business, you need a reliable vehicle that will provide you with what you need to transport your food, linens, and other supplies. Generally speaking, you're better off buying gently used, because you will...