Auto Theft

[Myfirstz71]

I used to pull the fuel pump fuse on a work car (Ford) because there were numerous extra keys around. Only challenge i ran into was sometimes the the starter kept turning like something was stuck. Possibility of burning up the starter? Kill switch would accomplish the same thing but be much more convenient

 

[01dailey]

I used to pull the fuel pump fuse on a work car (Ford) because there were numerous extra keys around. Only challenge i ran into was sometimes the the starter kept turning like something was stuck. Possibility of burning up the starter? Kill switch would accomplish the same thing but be much more convenient

I'm not sure what would make this happen. There would be no change to the system while kill switch is in closed position. If there is an attempt to start it while the switch is open (disabled), maybe the ECM is looking for increasing RPM indicating the engine has started ? It doesn't see it so it keeps cranking? Seems like there would be a time limit. I guess I would rather risk replacing a starter than a whole vehicle.

 

[Doubeleive]

I'm not sure what would make this happen. There would be no change to the system while kill switch is in closed position. If there is an attempt to start it while the switch is open (disabled), maybe the ECM is looking for increasing RPM indicating the engine has started ? It doesn't see it so it keeps cranking? Seems like there would be a time limit. I guess I would rather risk replacing a starter than a whole vehicle.

how many times do you think a thief is going to try and start it?.... the starter being ran is the least of your worries
1st they have to either jimmy the door lock or just break a window.
in either case you are not alerted, but I am because I added my own alarm with impact, tilt and glass sensors. If it gets triggered I get a text, a email, the fob vibrates and tones if it is within 1 mile and my phone app sounds a alert. All fine and dandy as long as I am within striking distance. the vehicle also flashes interior and exterior lights, vehicle horn + alarm horn + interior horn (added). makes a ruckus for sure. then they have the option to either rip the dash cover off and tear out the alarm or disconnect the battery. the 4g /gps tracker is buried way up under the dash behind the instrument cluster and has a separate power connector finding it will be a chore.

 

[01dailey]

This may be the stupid question of the day, but on the 2021 Yukon, how can I find the Fuel Pump Relay ? The owners manual lists all the fuses but they don't identify the relays. By the way, I see no listing for a fuel pump fuse either, unless there's another name for it or abbreviation.

 

[WalleyeMikeIII]

This may be the stupid question of the day, but on the 2021 Yukon, how can I find the Fuel Pump Relay ? The owners manual lists all the fuses but they don't identify the relays. By the way, I see no listing for a fuel pump fuse either, unless there's another name for it or abbreviation.

Relays are listed. Not sure which one is the fuel pump relay.

 

[01dailey]

Relays are listed. Not sure which one is the fuel pump relay.

View attachment 392830

I still see no Fuel Pump relay. I guess I could use the starter motor relay instead.

 

[WalleyeMikeIII]

I still see no Fuel Pump relay. I guess I could use the starter motor relay instead.

"Powertrain" might get it done, or Run/Crank....

I searched the Electrical Manual at the GM Upfitter site, it makes reference to a Fuel Pump Relay control from the Engine Wiring Harness to the Chassis Wiring harness; but didn't specify where the relay is...there is something called the "Fuel Pump Control Module" so this thing may be more complex than your dad's Oldsmobile.

 

[01dailey]

"Powertrain" might get it done, or Run/Crank....

I searched the Electrical Manual at the GM Upfitter site, it makes reference to a Fuel Pump Relay control from the Engine Wiring Harness to the Chassis Wiring harness; but didn't specify where the relay is...there is something called the "Fuel Pump Control Module" so this thing may be more complex than your dad's Oldsmobile.

I did some more research and discovered that my Yukon has a "Fuel Pump Power Control Module". This module is mounted on the driver side frame. This module varies the voltage to the fuel pump based on engine conditions. It also has control on/off of the fuel pump relay by control of the relay ground. I wonder if it contains the fuse and relay.

I also discovered that the 2019-2022 Sierra has the identical fuse box in the engine compartment as the 2021 Yukon. In the diagram it clearly shows the relay and fuse for the #2 Fuel Pump, but there is no relay/fuse for #1 Fuel Pump. I believe #2 is for the optional extra gas tank. I believe it also has a "Fuel Pump Power Control Module". Again, maybe this contains the relay/fuse.

 

[WalleyeMikeIII]

I did some more research and discovered that my Yukon has a "Fuel Pump Power Control Module". This module is mounted on the driver side frame. This module varies the voltage to the fuel pump based on engine conditions. It also has control on/off of the fuel pump relay by control of the relay ground. I wonder if it contains the fuse and relay.

I also discovered that the 2019-2022 Sierra has the identical fuse box in the engine compartment as the 2021 Yukon. In the diagram it clearly shows the relay and fuse for the #2 Fuel Pump, but there is no relay/fuse for #1 Fuel Pump. I believe #2 is for the optional extra gas tank. I believe it also has a "Fuel Pump Power Control Module". Again, maybe this contains the relay/fuse.

At this point, unless you can get the actual vehicle schematics, I believe you are just guessing...Possible the Diesel has two fuel pumps and this same fuse box is used for both? That may also explain why there are two relays...again...you need the schematics to get any further. My suggestion, get a consumer subscription to Alldata for a month, and get the data you need...vs guessing.

Honestly, I am not even sure your theory that it is easy to clone your keyfob/steal your ride is even valid...GM goes to great care to minimize auto theft. But, like you said, if you are afraid of the driveaway theft, you could accomplish the same thing by pulling the starter relay, right?

 

[01dailey]

It's pretty well known that keyless technology has become easy to defeat. There are RF signal repeaters on the market that will defeat your keyless system for as low as $20, going up in price costing thousands. I found this one on the web. The distribution center is Houston TX.

It doesn't take a lot of skill and you don't have to be some kind of computer geek to defeat a cars keyless entry system using the available devices for sale on the web. There are YouTube videos that give how to instructions and tell you what you need to buy. There are also classes available in automobile hacking.

There are things you can do to help prevent this type of attack. If your key fob has the capability, simply turn off the keyless function and use the buttons on the fob instead. Store the fob is a Faraday pouch or wallet to block the signal. Install a hidden kill switch in the vehicle or some kind of immobilizer that is not radio controlled.

Keyless Car Crime: How To Thwart The Thieves

Over the past five years the number of stolen vehicles has almost doubled, according to Home Office figures, and it seems that keyless car technology could

www.forbes.com