Security and CASE Relearns


If you send in your own PCM, you do not need to do a security or CASE relearn. If you install a core PCM and the vehicle does not start, you will need to do a security relearn. This occurs about 75% of the time. If you install the PCM and your vehicle does start, you do not need to worry about the security relearn. Security relearn instructions are included with your purchase. Try not to read too far into it, just do as it says. When in between steps, allow the security light to turn off before trying to start the vehicle. Also make sure you cycle through the relearn for at least four cycles or until the vehicle starts. If you cannot get through the security relearn, unplug the battery for about 10 minutes and then try it again, or perhaps have a friend try it for you.

A CASE relearn is a Crank Angle Sensor Error relearn, which realigns the position between the crankshaft position sensor and the camshaft position sensor. This relationship helps the vehicle determine advanced misfires. Anytime you install a new PCM into your vehicle that you intend to run long term, you need to have the CASE relearn done. So, this would apply to any of our core programs. The CASE Relearn can be done by anyone with a Tech 2 scan tool, advanced snap-on scanner, or also a Dashhawk or Aeroforce Scan Gauge depending on the vehicle. It is a 5 minute procedure. Cost will vary depending on where you go – you may want to call around first before deciding between the core program or loaner program. The CASE relearn will not keep the vehicle from running, however it should be done within at least two weeks of installing the new PCM. Once the CASE relearn is done, it’s done. You do not have to redo it if you switch back to your stock PCM or unplug the battery.

Security Relearn Procedure

 If the car does not start after installing the PCM, perform the security relearn procedure:

After installing the PCM, most of the time you will need to perform a Security Relearn Procedure. This can be done at your home and requires no tools. If your vehicle starts after installing the PCM, you do NOT need to do it.

  1. Attempt to start the truck by turning the key to the Start/Run position. Try to crank the vehicle.
  2. Observe that the vehicle fails to start and the security light is illuminated.
  3. Release key to the ON/RUN position (not the ACC position or OFF)
  4. Allow the vehicle to sit with key in the ON/RUN position for no less than 11 minutes. Security light will turn off after this.
  5. When the light goes off, turn key to OFF position and allow the vehicle to remain in the OFF position for no less than 30 seconds.
  6. Repeat #1-#5 for four cycles or until vehicle starts.

NOTE: Since this is a fairly long procedure (35 minutes) I would limit all electrical sources, such as shutting off headlights and AC fans to prevent discharge of battery. It is safe to wait longer than the allotted times above, but it is not safe to wait less.


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