How do thieves circumvent the passlock theft deterrent?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
23,706
Reaction score
34,649
Location
Stockton, Ca.
Better yet use a timed-off system that allows the fuel pump to run for like 2 or 3 minutes. Let them get out on the road then kill it. Their less likely to hang around trying to get it going again when they're dead in the middle of the road attracting attention!!
pfft 2-3 minutes I could be miles away
 

RST Dana

Supporting Member
Joined
Jan 15, 2018
Posts
1,489
Reaction score
1,222
Location
OH
Unless you keep it parked in 4wd. Wreckers now days can snag up the rear and and be gone before you can open your bedroom window and get radar lock. Keep it insured, get a tracking alarm, and park it in a “safe” location. Remember, chances are, yours is not a unicorn, and if all fails, then you can get another ride…
 

TJ Baker

Full Access Member
Joined
Mar 5, 2018
Posts
163
Reaction score
138
pfft 2-3 minutes I could be miles away

In that case I could set it to die in say .25 miles. Or once it reached a speed of my choosing. Maybe just cut the fuel if the rpm went above 1200. I can do any of this with my 05 Yukon if I choose to.
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
23,706
Reaction score
34,649
Location
Stockton, Ca.
In that case I could set it to die in say .25 miles. Or once it reached a speed of my choosing. Maybe just cut the fuel if the rpm went above 1200. I can do any of this with my 05 Yukon if I choose to.
why even let it be started to begin with? a secret cut off switch solves the entire issue
 

TJ Baker

Full Access Member
Joined
Mar 5, 2018
Posts
163
Reaction score
138
why even let it be started to begin with? a secret cut off switch solves the entire issue


On a nice quiet street a thief could spend a half hour or more checking things out. Just might find your switch since it logically would be within a drivers reach. But if the truck dies in the middle of the road it's far more likely to draw attention to the thief as they try to get it restarted. More likely to just bail.

Where I am theft is not a real concern anyway. Hell, the house and cars are generally left unlocked.
 

TJ Baker

Full Access Member
Joined
Mar 5, 2018
Posts
163
Reaction score
138
Getting back on topic, just in case anyone is interested.

Circled here is the actual resistor on an actual passlock sensor circuit board that varies from vehicle to vehicle and produces the variable voltage drop that the BCM sees and evaluates.

IMG_20210310_185719~2.jpg


The component with the blue dot is the passlock sensor that the small magnet in the rotating lock cylinder triggers. There is a second one beneath that one that is the tamper sensor. If the magnetic field isn't just right (too strong) that second sensor triggers and switches in another resistor of lower value and that drops the signal voltage very low and the BCM then knows to lock out the engine.
 

DougAMiller

Full Access Member
Joined
Mar 10, 2016
Posts
486
Reaction score
781
Location
Colorado
Hello

Yesterday I watched a video of someone stealing an 03-07 Silverado in under a minute. The thief pops the driver door then appears to do something around the column, I assume rip the covers off, and then starts the truck and drives away. I have a 03 Suburban so I want to try to protect it the best I can. Obviously towing it is still a possibility. Does anyone know how they bypass the ignition key passlock system? I've seen many trucks and SUV this style on insurance auction sites that are theft recoveries, and they always have the steering column covers broken open, so I know it happens/starts there. I'm not looking for specific instructions obviously, but in general. Do they just force the lock, and it starts due to a flaw in the system or is it more sophisticated? I've been searching the forums but nothing comes up. It does not appear the in the truck in video I watched has onstar because I don't see the antenna on top, so I don't think it's through that.

Brian
They tried to steal mine this way a couple of years ago, so I can explain the procedure. First they punch the lock cylinder in the driver's door. The door handle and base are plastic and hitting the cylinder hard will break the plastic ears that hold the cylinder in. Then it is a simple matter of turning the entire lock cylinder to unlock the truck, which also turns off the factory alarm.

The ignition cylinder is forced by ripping away the column cover to expose the protruding end of the cylinder and using vise grip or channel lock pliers to force it to rotate. There is a steel pin that prevents this, but the cylinder housing is aluminum, so they are trying to break that. The Passlock is entirely contained in the ignition lock cylinder and housing, the key has nothing to do with it, so if you can turn the cylinder the Passlock system is happy and lets it start. Getting the locking pin housing to break is a 50/50 proposition and depends partly on how good of a grip they get with the pliers. In my case they twisted off the end of lock cylinder instead and couldn't get another good bite on it with the pliers, so they gave up at that point. Sometimes, instead of pliers, they drive a screwdriver into the ignition lock cylinder and try to force it by using some kind of lever to rotate the screwdriver, but again, sometimes the soft metal of the lock cylinder gives first.

There are products out there that try to interrupt this method, like the Club or Jimmi Jammers, but from my research I don't think any of them are more effective than a good aftermarket alarm or a hidden kill switch, as others have been suggesting. Back when mine was broken into I had modelled the door handle base in CAD and was planning to have it machined from aluminum or steel so that they couldn't punch out the door lock, but before I got finished with that project I got a new Escalade, so never did get any made.
 

Doubeleive

Wes
Supporting Member
Joined
Nov 7, 2017
Posts
23,706
Reaction score
34,649
Location
Stockton, Ca.
On a nice quiet street a thief could spend a half hour or more checking things out. Just might find your switch since it logically would be within a drivers reach. But if the truck dies in the middle of the road it's far more likely to draw attention to the thief as they try to get it restarted. More likely to just bail.

Where I am theft is not a real concern anyway. Hell, the house and cars are generally left unlocked.
apparently the hidden switch is not well thought out on your end there are a million ways it could be done, a simple relay can be wired to just about anything including a magnetic switch. placing a magnet (on your keychain) against the switch (hidden practically anywhere) could trigger the relay on/off, including inside a door panel.
and I think you are giving the common thief a bit more credit than they deserve, most are about as bright as a box of rocks
 

TJ Baker

Full Access Member
Joined
Mar 5, 2018
Posts
163
Reaction score
138
apparently the hidden switch is not well thought out on your end there are a million ways it could be done, a simple relay can be wired to just about anything including a magnetic switch. placing a magnet (on your keychain) against the switch (hidden practically anywhere) could trigger the relay on/off, including inside a door panel.
and I think you are giving the common thief a bit more credit than they deserve, most are about as bright as a box of rocks

I agree, I don't spend a lot of time on the grade school level relays and switches these days.

My current project is an Arduino that reads all messages on the serial data bus and I can choose any given message to trigger any given action that a Tech 2 could do in response, short of reprogramming of course.
 
OP
OP
B

briand069

TYF Newbie
Joined
May 17, 2014
Posts
7
Reaction score
0
They tried to steal mine this way a couple of years ago, so I can explain the procedure. First they punch the lock cylinder in the driver's door. The door handle and base are plastic and hitting the cylinder hard will break the plastic ears that hold the cylinder in. Then it is a simple matter of turning the entire lock cylinder to unlock the truck, which also turns off the factory alarm.

The ignition cylinder is forced by ripping away the column cover to expose the protruding end of the cylinder and using vise grip or channel lock pliers to force it to rotate. There is a steel pin that prevents this, but the cylinder housing is aluminum, so they are trying to break that. The Passlock is entirely contained in the ignition lock cylinder and housing, the key has nothing to do with it, so if you can turn the cylinder the Passlock system is happy and lets it start. Getting the locking pin housing to break is a 50/50 proposition and depends partly on how good of a grip they get with the pliers. In my case they twisted off the end of lock cylinder instead and couldn't get another good bite on it with the pliers, so they gave up at that point. Sometimes, instead of pliers, they drive a screwdriver into the ignition lock cylinder and try to force it by using some kind of lever to rotate the screwdriver, but again, sometimes the soft metal of the lock cylinder gives first.

There are products out there that try to interrupt this method, like the Club or Jimmi Jammers, but from my research I don't think any of them are more effective than a good aftermarket alarm or a hidden kill switch, as others have been suggesting. Back when mine was broken into I had modelled the door handle base in CAD and was planning to have it machined from aluminum or steel so that they couldn't punch out the door lock, but before I got finished with that project I got a new Escalade, so never did get any made.
Thanks for this information. This confirms what I was thinking and lines up with what is seen on the video I watched of the truck being stolen. The guy appears to push something into the driver's door, once inside the truck, it is started in less than 30 seconds and is gone. I knew about the factory alarm being bypassed by punching the lock, so the logical choice would be to install a standalone alarm system with a starter disable to not make it so easy. And maybe something else that would be a deterrent for someone looking for a fast easy steal. I suppose if you could disconnect the factory alarm from the door lock so it isn't easily defeated could also help. I realize someone determined to steal something will do whatever it takes, but considering how easy it easy to steal this era truck/SUV it's not surprising it happens so often.

Brian
 

Forum statistics

Threads
129,203
Posts
1,812,059
Members
92,303
Latest member
44Dan
Top