im having a problem with the crank relearn

[whackem04]

I have let the truck warm up, have the truck in park, foot on the brake and i press the button to relearn and nothing happens or it says no reply try again.
Anybody else used it lately? am I missing something?

[joecar]

After you click the button, you have about 10 seconds in which you have to increase throttle to bring the RPMs upto above 4000 or 4500...

when you hit the right RPM, the PCM will cut fuel momentarily causing stumble for a brief moment, you will notice it...

immediately when it stumbles, release throttle and let engine spin down to idle on its own...

after reaching idle wait a few seconds and then turn engine off (key all the way to OFF), and wait at least 15 seconds with key off.


Also note: for this to work ECT must be in the specified range, in addition to brake switch indicating brake pedal applied.

[whackem04]

thanks! ill try it again. does it let you know that it has completed?

[joecar]

thanks! ill try it again. does it let you know that it has completed?The stumble indicates that the relearn has initiated...

after the stumble, when you let the engine spin down on its own, the PCM collects data... one of the things it collects is the natural rate of deceleration of the crank... this is later used by the misfire algorithm.

it doesn't let you know that it's finished... but the stumble lets you know that it has initiated.