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Chevrolet Express
Platform: GMT Van

2001 Express BCM location?

Old October 24th, 2018, 4:27 AM
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Your van does not have a BCM. It has Vehicle Theft Deterrent (VTD) module inside the instrument panel, and it sends a password to the PCM, which enables the fuel injectors. You cannot bypass it. The purple wire is the data line.

(from GM PassKey and PassLock overview - Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice | Automotive Repair Tips and How-To)
The PassLock system works when the lock cylinder moves a magnet past a Hall effect sensor ... This system proved VERY unreliable as the Hall effect sensors had an extremely high failure rate. To repair the system, the shop would have to replace the lock cylinder housing because the Hall effect sensor can’t be replaced separately.

From GM

30 Minute Learn Procedure
  1. Turn ON the ignition, with the engine OFF.
  2. Attempt to start the engine, then release the key to ON, vehicle will not start.
  3. Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
  4. Turn OFF the ignition, and wait 5 seconds.
  5. Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes. The vehicle is now ready to relearn the Passlock™ Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK. (Important: The vehicle learns the Passlock™ Sensor Data Code and/or password on the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.)
  6. Start the engine. The vehicle has now learned the Passlock™ Sensor Data Code and/or password.
  7. With a scan tool, clear any DTCs if needed. The history DTCs will self clear after 100 ignition cycles.


If the anti-theft system is being triggered or malfunctioning, the security light should come up on your dash and there will be associated trouble codes. Without those, it is very difficult to determine which, if any, component is malfunctioning. Or you might have a bad wiring connection somewhere.

P0101 and P0107 are air intake related problems, which could prevent the engine from running. The codes could conceivably be symptoms of the first issue.
Old October 24th, 2018, 3:03 PM
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Originally Posted by mountainmanjoe
Your van does not have a BCM. It has Vehicle Theft Deterrent (VTD) module inside the instrument panel, and it sends a password to the PCM, which enables the fuel injectors. You cannot bypass it. The purple wire is the data line.

(from GM PassKey and PassLock overview - Ricks Free Auto Repair Advice Ricks Free Auto Repair Advice | Automotive Repair Tips and How-To)



From GM





If the anti-theft system is being triggered or malfunctioning, the security light should come up on your dash and there will be associated trouble codes. Without those, it is very difficult to determine which, if any, component is malfunctioning. Or you might have a bad wiring connection somewhere.

P0101 and P0107 are air intake related problems, which could prevent the engine from running. The codes could conceivably be symptoms of the first issue.
Thank you for this information. I found a module that might be the VTD. Since this van is an export vehicle I think it has a different version. The fobs use another frequency in Europe. I post a pic of it.



What about the https://newrockies.com/passlock-bypass-2/ module, anyone here tried it and if so, did it work?
Old October 24th, 2018, 5:34 PM
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Vehicles for export are different. They have a Vehicle Immobilizer Module (VIM) instead. (Yes that's it there in your photo, mounted above the engine cover)
The relearn procedure probably won't work for you then. I don't know exactly how it works unfortunately. But it does communicate over the serial bus.
This is all I could find:
Transmitter Programming Procedure (Export)
An override code is used to disable the vehicle immobilizer module (VIM) and allow keyless entry transmitter programming. The override code is a 5 digit number which is entered into the VIM at the factory. The VIM override code may be entered manually or with a scan tool.To determine the code and enter the override mode manually, perform the following:
  1. Insert the ignition key into the ignition lock cylinder
  2. Cycle the ignition ON, OFF, ON within 2 seconds.
  3. The security indicator will flash the number of times equal to the first digit of the override code.
  4. Press the brake pedal to enter the digit.
  5. The security indicator will twelve times within 4 seconds in order to verify the input of the digit.
  6. Repeat the previous step to enter the next 4 digits of the override code as the digits are flashed by the security indicator.
If the incorrect override code is entered the security indicator will turn off immediately and the VIM does not enter the override mode. When the correct override code is entered the security indicator will illuminate for approximately 10 seconds. The immobilizer is inactive and the transmitters may be programmed.
Old October 25th, 2018, 2:58 PM
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Originally Posted by mountainmanjoe
Vehicles for export are different. They have a Vehicle Immobilizer Module (VIM) instead. (Yes that's it there in your photo, mounted above the engine cover)
The relearn procedure probably won't work for you then. I don't know exactly how it works unfortunately. But it does communicate over the serial bus.
This is all I could find:
Thank you for this. Seems like I will need the 5 digit number code which I don´t have.
The van starts every tenth or so attempt so I´m not completely stranded but it would be nice to get this crappy system bypassed.
Old October 25th, 2018, 3:36 PM
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steps 1 through 6 explain how to obtain the code.
Old October 25th, 2018, 11:19 PM
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Originally Posted by mountainmanjoe
steps 1 through 6 explain how to obtain the code.
I need to read more thoroughly Again, thanks.
Just so I understand this correct:
Do I use the override code just to be able to reprogram the fobs or program new fobs to the van or could I leave the immobilizer in the inactive mode permanently?

I have one working fob and that one always closes/opens the doors and turns off/on the alarm as it should.
But still, the van won´t start most of the times.
Could it still be worth doing the 6 step process?
Old October 26th, 2018, 12:05 AM
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Sorry I wish I could tell you more. The instructions say it will disable it.
Old October 26th, 2018, 2:59 AM
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Originally Posted by mountainmanjoe
Sorry I wish I could tell you more. The instructions say it will disable it.
Thanks anyway, you were very helpful, appreciate it.


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