ECM and Immobilizer Programming

[Chevrolet, Buick, Cadillac, GMC]


⚠️ Read notes on GM’s Global A Architecture, before swapping used parts.


10 mins relearn
30 mins relearn
  • Step 1. Attempt to start the vehicle (won’t start), then release the key to ON.
  • Step 2. Leave ignition in the ON position for 10 mins
  • Step 3. Turn ignition OFF for 5 seconds
  • Repeat Step 2 and Step 3 two more times.
  • Step 4. Turn ignition OFF and then 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.


Pass Lock Disable
Tech 2
  • Tech 2 has an option called “VTD option reset” (1998 Chevy Cavalier 2.2L)
  • It disables the Antitheft system.
  • Works best with unplugged passlock at the steering column. If to leave it plugged in, the car might not start.
Resistor Bypass
  • Put a resistor (e.g. 2k) between passlock signal (yellow) and ground (black) wires.
    • Sensor signal voltage should be lower than 5V. With 2k resistor should be around 2.3V.
    • “Passlock Code” should say “Valid Code x” (x=number)
  • Perform 30 mins relearn.

PCM Replacement Notes

  • Buy SPS Subscription.
  • Reprogram ECM
    • Don’t forget to enter a different VIN and the very beginning, or you will loose your purchased subscription for one VIN
    • Disconnect any aftermarket equipment. Sometimes need to disconnect communication wires to the other modules, having only PCM communicating with a scan tool.
  • Go to Vehicle Deterrent System Relearn.
    • Note: Don’t go to Theft Deterrent System Reprogramming, it will not match ECM and immobilizer.
  • If diesel,
    • perform Injector Flow Rate Programming
      • Autel   ➱ Glow Plug Module ➱  Copy Flow Rate Calibration from GPM to ECM
      • Clear codes
  • 📝 ECM Reprogramming | 2004 Chevy Trailblazer
    • Tried to reprogram two different used ECMs with the same part number as the original.
      • SPS has started programming fine, but the last 10-11 seconds stopped with the Programming Error.
      • Before programming it asks to remove two fuses from the rear fuse box, but this hasn’t helped.
      • Without programming car doesn’t start.
    • Probably needs a new ECM.
      • Customer declined repair, so cannot test this hypothesis.

BCM Replacement Notes

  • With used BCM
    • Remote start won’t work until CKP Relearn has been done.
    • Navigation might display Theftlock
    • Remote control /start not work
    • 2007 Cadillac Escalade
      • Swap 93C66 memory and perform CKP relearn
    • 2014 Chevy Suburban
      • SPS programs used BCM just fine.
      • Even without programming, the car started, but had few issues  that were fixed after programming.

Key Programming Notes

  • 2012 Chevy Aveo. X100. Program key and remote.
  • 2013 Chevy Cruze. X100. Extracted pin code ok.



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