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Attention: Disconnecting battery DOES not clear the ECU adaptation values

14K views 16 replies 9 participants last post by  KevinJ_2k1_325ci 
#1 ·
This is a confirmation from a master tech I know who worked for the BMW dealership for about 10 years. I spoke to him about the "disconnect battery and leave for 10mins" trick. He confirms with me that that is only for pre-1993 BMWs, not for our E46s anymore.

In order to clear the ECU adaptation values, you have to approach the dealer and hook up your car to the MoDIC.

If you somehow "feel" the difference with the battery trick, that is more likely to be psychological. I had the values cleared the right way and trust me, the car feels totally different.

So spread the truth!:thumbup:
 
#2 · (Edited)
What happened to turning the key to accessories for 10 seconds, off for 10 and start the car??? This at least clears throttle adaptation.

I never felt a difference doing the battery "trick" only doing the throttle adaptation has made a difference. The throttle adaptation reset is published information I found in the TIS.

This at least helps for a short period but I found that at least in the begining after a reset, performance drops, then climbs after some amount of driving like a day or two, then after three or more days performance levels off.

SO this confirms that there are large implications to putting performance mods on our cars. It may be that we are getting false impressions of a mods performance because the old adaptations are still there. So what happens after a week or two of driving when those mods are adapted out? It seems as software is necessary to raise limits so that this is not the case BUT then as pointed out, upgrading software WILL NOT erase adaptation values. You still have to go to the dealer.

Do you have more information Mr. Paddle Shift to expand on this? Also I posted a while ago about BMW's definition of a electronic throttle and that it has two modes, sport and non-sport. Is there a way to switch the sport throttle mode on? I'm not talking about steptronic sport mode but throttle mode.

Mr Paddle.Shift said:
This is a confirmation from a master tech I know who worked for the BMW dealership for about 10 years. I spoke to him about the "disconnect battery and leave for 10mins" trick. He confirms with me that that is only for pre-1993 BMWs, not for our E46s anymore.

In order to clear the ECU adaptation values, you have to approach the dealer and hook up your car to the MoDIC.

If you somehow "feel" the difference with the battery trick, that is more likely to be psychological. I had the values cleared the right way and trust me, the car feels totally different.

So spread the truth!:thumbup:
 
#3 ·
That's weird,

the master tech over at my stealership confirmed that disconnecting the battery for 15 minutes cleared the adapative transmission, etc from the ECU.

Could US models be impervious to this method of clearing the ECU?
 
#4 ·
The information I have from the TIS is.

Basically the tech must clear the adaptation. I've only heard about clearing by battery method like Paddleshift said on pre-1993 from information on the net. It's people who proported that you could still do it on 1993 and above but I've tried a battery reset myself and noted NO difference. If adaptation was cleared you would notice it like clearing throttle adaptation.


Asmodeus said:
That's weird,

the master tech over at my stealership confirmed that disconnecting the battery for 15 minutes cleared the adapative transmission, etc from the ECU.

Could US models be impervious to this method of clearing the ECU?
 
#5 ·
Kevin,

there is no sport mode for the TB. What the Z4 2.5L has is a different ECU program as well to make use of the sport button.

One more thing about clearing adpatation values. When the DME unit has cleared the stored values, the engine could lead to an erratic idling and disturbed over-running after starting. This happens for a while til the new input values are adapted into the DME. I seriously don't recall that actually happened with the battery trick, but it did happen with the MoDIC hooked up. The engine revved up on its own for a while before settling down.
 
#6 ·
I am thinking that if one does not experience check engine light errors that reset the adaptation tables is not necessary. This could be with a CAI or SC. How long does it take for the tables to adjust to say a SC especially if the car is rather new (i.e. 3000-5000 miles)

I do think the throttle adaptation is a different procedure as described earlier (i.e. 10 seconds on/off).
 
#8 ·
Yes throttle adaptation works.

What Mr. Paddleshift is referring to is the stored ECU adaptation values for everything else such as spark, fuel, air/fuel ratio, peddle pressure, etc. The throttle adaptation values can be cleared by the procedure I posted a while ago, turn key from off position to accessories (on position but car not started), wait 10 seconds, turn to off position for 10 seconds then immediately start car. You will note a difference. But if you did it wrong like 11 seconds and 10 seconds you will note no difference.

330iCanada said:
I am thinking that if one does not experience check engine light errors that reset the adaptation tables is not necessary. This could be with a CAI or SC. How long does it take for the tables to adjust to say a SC especially if the car is rather new (i.e. 3000-5000 miles)

I do think the throttle adaptation is a different procedure as described earlier (i.e. 10 seconds on/off).
 
#16 ·
Vince, all we have to do is go to the dealer and ask them to reset the adaptation values? How much will that be? If we get the Dinan software or shark will that do same thing?

TIA,
Charlie
 
#17 ·
As far as I know, the shark does not reset adaptation.

Dinan might do it since they have your car in their shop and have the proper equipment. As far as I know the shark does not reset adaptation. I saw a thread written by Jim on this once.

Yellowmann said:
Vince, all we have to do is go to the dealer and ask them to reset the adaptation values? How much will that be? If we get the Dinan software or shark will that do same thing?

TIA,
Charlie
 
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