Reprogramming Computer for Alternator/Battery Change?

[pureco99]

I was told the car's computer needs to be re-programmed to recognize a re-built alternator and brand new battery has been replaced. After re-built alternator and new battery has been replaced, independent mechanic stated there are some communication problems between the car's computer and new alternator. Not sending signal to alternator to start. It looks like I will have to spike the Alternator and drive it to dealership to get it re-programmed. Does anybody know if this is true? I'm in a pickle here. Thanks!

[Bubblehead 323i]

That is a requirement for E90 class when you replace the battery. Should not be required for E46s. Something else wrong? Fuses? Relays?

[pureco99]

Maybe the relay. Honestly, I'm too ignorant about the relay and what its function is.

bump bump

[Bubblehead 323i]

http://blog.bavauto.com/bmw-e46/no-start-1989-325i-e30

Above link is a troubleshooting checklist for no-start problems.

[danewilson77]

I was told the car's computer needs to be re-programmed to recognize a re-built alternator and brand new battery has been replaced. After re-built alternator and new battery has been replaced, independent mechanic stated there are some communication problems between the car's computer and new alternator. Not sending signal to alternator to start. It looks like I will have to spike the Alternator and drive it to dealership to get it re-programmed. Does anybody know if this is true? I'm in a pickle here. Thanks!

I have never heard of this.

[genuity]

I have never heard of this.

+1

E46's do not require any reprogramming of any kind after replacing battery or alternator. I have replaced both without problems of any kind. It does not matter if the alternator is rebuilt or brand new either. It's those newer generations that you maybe looking at that, so be glad you don't have one where you cannot service yourself. You will be glad to hear you do not loose your radio presets when unplugging the battery. The only memory type issues you will loose is the OBC's memory: MPG, time, avg MPG, and avg Speed. Don't be surprised that after your first commute you are getting 40 MPG or something ridiculously high. Give it some time and it will average back to normal and maybe not even change at all. I had it where my MPG would not even change 0.1.

[TerraPhantm]

Only need it for the most-bus based cars since they have the so-called intelligent charging systems that vary the charging time and things like that based on the age of the components.

[pureco99]

this is an excerpt I got from another forum, "AND WHEN YOU ALL HAVE REPLACED YOUR BATTERYS...-> GO TO DEALER AND REGISTER BATTERY REPLACEMENT TO GET Engine electronics and alternator work like it should work...and to get IBS (intelligent battery sensor) work properly. If you change bigger battery -> car has to be updated!!" - that being said, I also forgot to mention my car's computer was updated with new software early last year after the infamous hesitation problem (such update fixed that problem). I'm still thinking...

[02325]

THERE IS NO PROGRAMMING ON ALTERNATOR OR BATTERY ON A E46. You just replace and go on your way. E90 06+ 3-series yes you have to reset the computers, not on a E46 99-06 3-series. They still made E46 coupes in 06.

[TerraPhantm]

this is an excerpt I got from another forum, "AND WHEN YOU ALL HAVE REPLACED YOUR BATTERYS...-> GO TO DEALER AND REGISTER BATTERY REPLACEMENT TO GET Engine electronics and alternator work like it should work...and to get IBS (intelligent battery sensor) work properly. If you change bigger battery -> car has to be updated!!" - that being said, I also forgot to mention my car's computer was updated with new software early last year after the infamous hesitation problem (such update fixed that problem). I'm still thinking...

Since only caps seem to register (no pun intended) with you: THERE IS NO BATTERY REGISTRATION FOR E46s. THE CAR HAS NO PROVISIONS FOR SUCH PROGRAMMING. If your alternator doesn't work, that means it's either broken or not installed properly. Your mechanic is just trying to shirk himself of his responsibility. For the e46 the alternator is always running - there is no intelligent charging system.

Your car's software being updated for hesitation has absolutely nothing to do with the battery. The only modules that can accept new software on the E46 are the DME (Digital Motor Electronics) and the transmission computer if you've got an auto. Obviously a software change on either (or both) of those components can result in the car behaving a little differently.

[Bubblehead 323i]

Since only caps seem to register (no pun intended) with you: THERE IS NO BATTERY REGISTRATION FOR E46s. THE CAR HAS NO PROVISIONS FOR SUCH PROGRAMMING. If your alternator doesn't work, that means it's either broken or not installed properly. Your mechanic is just trying to shirk himself of his responsibility. For the e46 the alternator is always running - there is no intelligent charging system.

Your car's software being updated for hesitation has absolutely nothing to do with the battery. The only modules that can accept new software on the E46 are the DME (Digital Motor Electronics) and the transmission computer if you've got an auto. Obviously a software change on either (or both) of those components can result in the car behaving a little differently.

Said this 2 days ago.

[pureco99]

apparently the re-built alternator the indy mechanic put in it wasn't producing the correct amount of power. Moreover, it looks like at the end he didn't know what he was doing. I had to take it to the stealership to be replaced and get the charging system fixed. So far no problems. I did pay quite a bit of money but at least the work and parts is guaranteed for 2 years.

[newtoe46]

Was it undercharging or overcharging?

[pureco99]

undercharging

[IWannaBMW]

The battery should have been disconnected when replacing the alternator. This will also reset the computer, but e46's don't require the reset for replacing an alternator. Battery must be disconnected to prevent voltage spikes etc.

[bmwbob89]

There are a lot of bad rebuilt alts out there. You just got a bad one. BMW alts are rebuilt units too. The cars that have the new systems started with the E65 then the E60 and E90. E-46 did not have the system. No resets or registrations required.