Does Cam / Crank Relearn Need To Be Done When Powered Down ECU Is Reinstalled?

[Powelligator]

Jeep is a 2006 LJ 4.6 Stroker.

1. When installing a new ECU (from WranglerFix for example) and that ECU has been powered down for weeks, will it automatically run the cam / crank relearn procedure on its own after initial startup - or - do you still need to connect a scanner (Innova or Foxwell) to manually do the cam / crank relearn? This is on a new engine, all new parts and the TDC positioning procedure was meticulously done by hand so I’m certain it’s all lined up. Jeep started fine, runs great, no codes.

2. What’s the correct way to plug in a scanner to the OBD port? I want live data, so that means the engine needs to be running. Do you plug the scanner into the OBD port *then* start the engine, or can you just plug the scanner into the port under the dash while the engine is running?

Thanks!

 

[GoldenGorilla]

I don't know the specifics on the 05/06 CPS relearn.

Regarding the scanner, most you can just plug in at any time, but I generally plug them in before I start the car. The ODB port is always power on, but the ECU is not powered on until you go to key on (not start).

 

[hear]

I plug my reader in hot all the time. I also unplug it while running. But I also don't always eject my usb drives before removing either. And on more than one occasion I've used an aerosol spray in a manner other than directed. So maybe you shouldn't listen to me.

 

[JKP]

My Wranglerfix PCM has been in there for yrs. I never performed a cam/crank relearn on it.

It's my understanding that the 05/06 will perform the relearn after the PCM has been powered down for an extended period of time. Can't prove it as I don't have a scanner that will read the learned value.