After having my Blackwing for a month, I performed the idle relearn as described here http://www.c5forum.com/diy/idlerelearn.php
The car seems to have picked up a step.

Can someone explain how this works to me ? I'm curious how the idle relearn resets the PCM, and exactly what functions of the PCM are set back. For instance, is the spark timing reset with idle relearn ? How does doing the idle relearn differ from disconnecting the battery ?

Please educate me about this, but I really think it works !! :yesnod:

 

I'm very interested too :confused: :confused: :confused: :confused:

If anyone knows please post :smash: :smash:


:flag :flag :flag :flag

 

If I were to venture a guess, somebody correct me if I'm wrong, since you turn the key to 'on' with the fuses disconnected, the other computers on the car's bus (BCM, etc), realize that there is no PCM available. They mark some status flag that says to send it a reset message when it comes onto the car's bus again. Then, you turn the car back off, put the fuses in, and turn it to on again, so the other computers send the PCM some reset message. This is probably done so they can swap a PCM in without having to reset it first, using some external tool.

 

I found the procedure on this forum. this link will take you to the page.
http://www.c5forum.com/diy/idlerelearn.php


C5 Idle Relearn Procedure
Purpose
This page basically shows you step by step how to do an Idle Relearn. You would want to do this if you have done any intake modifications. If you do not do this, you may have hesitation or other issues.

Tools Required
None.

Do the Job
Follow these procedures EXACTLY or you will have to start from scratch.

Insert key into ignition and turn to the "On" position but, DO NOT START THE ENGINE.
Pop open the engine fuse block box cover and remove the two 10amp fuses from position numbers 16 & 23.
Your DIC will now display "check" messages for ABS, etc...
Turn ignition to the "Off" position.
Re-insert both 10amp fuses for positions 16 & 23.
Start your engine
Allow engine coolant temperature to reach a minimum of 176 degrees F and run at this minimum temperature for at least 5 minutes.
Shut down engine
Let rest for a minimum of 30 seconds.
Restart engine - check for DIC error codes (there should be none).
Drive car for a minimum of 30 miles at varying rpm settings and speeds. PCM will now re-learn and adjust for the new air flow and air temperature at the intake.
This page was last updated on 06/06/01 by Redshift

 

If you've been driving regularly, you should have already had all the relearn needed. You can disconnect and clear the trims from the PCM or drive and the trims will learn. In fact they are always learning.