Yes I already searched but couldn't find the answers to my questions.

It says to rev to fuel cutoff (4000-5000 rpm)....I dont understand this. I thought fuel cutoff would be way up there like 7000 rpm. Heck a stock Ls1 revs to 5500-6000. So I'm not sure on that.

Do I slowly rev it up or quickly rev it up to fuel cutoff?

At the end it says to cycle the key. I just want to confirm that means shut the car off then to the key to the ON position, but dont start the car. Is this correct?

I have a "service vehicle " light on the dash.
Do I need to take care of this before the crank relearn procedure will work? I've read a few people say that you cant have any other codes when performing this.

Thanks

 

If is correctly running in CASE learn mode, it will cutoff at about 4k. If it will run to 5k or more then CASE learn is not running.

If the DTC is "CASE not learned" IIRC P0315, that's fine.

IIRC key off for 15 seconds the save the learn parameters to long term memory.

What tool is being used to get into case learn mode?

 

Clear any codes, vehicle usually needs to be warmed up I believe over 160 degrees maybe higher I don’t remember exact degree, vehicle in park or neutral, rev engine until v8 engine fuel cutout off which I believe is 4k rpm to run the test and then vehicle will cut off at 4k. If it does not cut off at 4k-5k then it didn’t do the crank relearn. You usually never have to rev the engine past 4500 for this procedure on any gm vehicle.

 

It's my understanding that the learning happens while RPM is falling, not while it's rising, so it doesn't matter if you stab the gas or ease into it.

After fuel is cut, RPM will of course come back down, and that's when the magic happens.

 

CASE: CRANK RELEARN

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.

A crank relearn is a process that the PCM goes through to recalibrate its knowledge of the relationship between the crankshaft and camshaft. That’s necessary because the crank and cam are connected by a timing chain or timing belt. Over time, the timing chain/belt can stretch and that stretch changes the relationship and timing between the crankshaft and camshaft.

If the change/stretch is great enough, the PCM will notice discrepancies between the commanded valve timing adjustments and the actual valve timing. That difference can cause misfires like P0300 or specific cylinder misfires.

You can try doing it yourself using the steps below...

1 - Turn off all of the accessories. With the Air temperature sensor and Coolant temperature within 5*C (41*F) of each other, start the engine and let it idle in Park or Neutral for two minutes.

2 - Accelerate the vehicle to 55 mph at part throttle. Cruise at 55 mph for 8-10 minutes until the engine reaches operating temperature.

3 - Cruise at 55 mph for another 5-6 minutes.

4 - Decelerate to 45 mph without using the brakes, and maintain 45 mph for 1 minute.

5 - Perform 4 deceleration cycles, without using the brakes, of 25 seconds each where no specific speed is necessary. Returning to 45 mph for 15 seconds in between deceleration cycles.

6 - Accelerate to 55 mph and cruise for 2 minutes.

7 - Stop the vehicle and idle for 2 minutes with the brake applied and the transmission in Drive (automatic trans.) or Neutral (manual trans.) with the clutch depressed.

If that doesn't work, then you'd need to take it to a dealer/shop and have the crank relearn done using their dealer-level scan tool...

 

Do those steps work with Gen III PCMs?