Jump to content

The RennTech.org community is Member supported!  Please consider an ANNUAL donation to help keep this site operating.
Click here to Donate

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Recommended Posts

The workshop manual states the following in connection with the battery change:

If the battery is replaced, both numbers (serial number and part number)must be entered in the gateway control unit under:

Gateway/Maintenance, repairs/Change battery


Can anybody  tell me what this means? Do you have to code something into the electronics of the vehicle when you change the battery?

Link to post
Share on other sites
    You can remove these ads by becoming a Contributing Member.

This is one of those.. "can't actually do this" sort of things. I read this same message, and after installing a new AGM battery (identical to the old one) called two different Porsche dealer service departments to ask about having it done. They both said "What?" "We don't do that.."  So I visited an independent with several different high-end code tools. The tools thought they could do it - but they couldn't. Wouldn't write to the ECU.  My DuraMetric doesn't even offer the option, so I bought an ICarScan tools that does - it offers to do it and then tells you it can't do it.


So I put a voltmeter up on the dash PCM multi-display as one of the lines in it. Found the system was happily charging away at around 13.2-13.5V no matter what (idle, higher engine speeds, more items on - it stayed the same..)  Somehow I then pressed the "sport" button and spotted the charge voltage immediately jumped 1V higher (14.2-14.5V). Switched off "Sport" and it dropped back down. Tried manually selecting gears to get the same engine RPM/speed - the voltage didn't change. Went into "sport" mode - voltage went up, manually selected a higher gear to drop RPM - voltage remained up.


So - figured out what the deal was - Porsche was maximizing MPG in "normal" mode. That's where the MPG rating is taken - not in sport mode. So by limiting the charge voltage and current, that minimizes the load on the engine, which ups MPG. In sport mode no one gives a darn about MPG - so they let it charge in a "normal" manner.


Given that - there is no reason to program the ECU to the new battery. The charge circuitry is more interested in MPG than maximum battery life. MPG costs Porsche $$ (gas-guzzler tax) - which costs sales.  The bean counters basically are setting your charging parameters.


Short version: Fugeddaboutit.



Link to post
Share on other sites
  • Moderators

All this system is trying to do is to record the battery install information for later retrieval during diagnostics.  It does not do anything, it just keeps the information with the vehicle as the owner typically is often vague about such minutia when asked. 

Link to post
Share on other sites

All this system is trying to do is to record the battery install information for later retrieval during diagnostics.  It does not do anything, it just keeps the information with the vehicle as the owner typically is often vague about such minutia when asked. 

JFP - I think the concern comes from the BMW family tree - where charge parameters were actually changed over the life of a battery to optimize the charge characteristics to match the battery age/use. Some early battery failures on BMWs have been blamed on the failure to reset the charging parameters when changing batteries.


As far as I can find - the charge voltages that Porsche uses are fine for any AGM battery that might be used... so no need to change the parameters.

Edited by deilenberger
Link to post
Share on other sites
  • Moderators

We have never seen any change in how the vehicle operates, regardless of what data is, or isn't entered into the system, so the conclusion is that it does not seem to matter, making it a data store more than anything else.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.