I really think that cpu reset is fairy tale.
ECU have hardcoded maps in it. And ecu uses them, it doesn't store anything in ECU memory. Based on many sensors and maps it calculates how much air, fuel and so on is needed.
ECU reset is just placebo effect, If not -then why need to disconnect battery for 45 mins? Does ECU have internal battery which lasts for 45mins? No. So it's enough 1min. Why need to idle for 15mins? WHy 15? does ecu loves human like time spans? Does ecu sooooooooo slow that it needs more than 30secs to do all it's job?
I had many cars but NEVER had any effects after so called "resets".
This whole reset crap is like bible - 100% people made bull**** story.
The only thing it resets-it's your radio
Wanna make sure it makes no difference? connect diagnostics to OBD look at how much fuel is injected on idle, on 2000 revs, 3000revs. then reset ecu.. and repeat test.
As I've said a number of times before, what is does at most is reset the throttle, depending on ECU type. (min/max and idle)
Disconnecting for 30' or so is just a ballpark figure to make sure ECU and BC are reset, there is a lot of capacitance in the system retaining voltage. It can be speeded up shorting the (disconnected !) minus battery lead with the positive.
15 minute idle (as specified in elearn) is again a ballpark figure to make sure engine reaches operating temp.
(and actually, on 147, gt etc what it doesn't
do is reset your radio
As a side note, in modern ECU's there are adaptive parameters that compensate for "normal" wear on certain parts, so yes, it does store certain adaptive parameters. However, these are NOT reset by this procedure....
The main operating principles of the system are basically as follows:
The control unit implements the self-learning mode in the following conditions:
- installation of new injection control unit,
- installation of a new throttle body actuator integratd with D.V.L.
- removing/refitting or replacement of rpm sensor/phonic wheel, for recognizing misfire.
The learnt values of the throttle body integrated with D.V.L. are preserved if the battery is disconnected.
The learnt values of the phonic wheel for recognizing misfire are instead lost.
The control unit has a self-adaption function which recognizes changes in the engine which occur as a result of bedding-in and ageing processes of both components and the engine itself.
These changes are stored in the form of modifications to the basic mapping, and their purpose is to adapt the operation of the system to the gradual alterations in the engine and components compared with their characteristics when new.
This self-adaptation function also makes it possible to even out inevitable differences (due to production tolerances) in any replaced components.
From the exhaust gas analysis, the control unit changes the basic mapping in relation to the original characteristics of the new engine.
The self-adaptation parameters are not cancelled if the battery is disconnected