Results 1 to 10 of 10

Thread: Help with Ike voltage issue 2001 740

  1. #1
    Join Date
    Nov 2018
    Location
    Atlanta
    Posts
    16
    My Cars
    2001 740i

    Help with Ike voltage issue 2001 740

    My 740i has a lot of intermittent IKE display issues. When I do my IKE test 9 I get 6.9 volts while the battery tests normal at 12.5

    I know the I bus needs above 7v for reliable data comms and that the IKE is both a multibus gateway and a standby controller and voltage supplier for the I bus.

    Is this the problem? Can I do anything other than replace the LCM ( I bus master controller) and IKE?

    Are there any other options? Maybe the ignition switch is not providing proper voltage to the IKE?

    Any ideas on troubleshooting?

    john
    2001 740i
    Last edited by Ltbordo; 11-26-2018 at 11:39 AM. Reason: Spelling

  2. #2
    Join Date
    Aug 2017
    Location
    Wayne,PA
    Posts
    1,511
    My Cars
    740iL (E38 '01)
    Quote Originally Posted by Ltbordo View Post
    My 740i has a lot of intermittent IKE display issues. When I do my IKE test 9 I get 6.9 volts while the battery tests normal at 12.5

    I know the I bus needs above 7v for reliable data comms and that the IKE is both a multibus gateway and a standby controller and voltage supplier for the I bus.

    Is is this the problem? Can I do anything other than replace the LCM ( I bus master controller) and IKE?

    Are there any other options? Maybe the ignition switch is not providing proper violate TO the IKE?

    Any ideas on troubleshooting?

    john
    2001 740i
    After the battery, I would replace the ignition switch whenever there is a voltage issue.

  3. #3
    Join Date
    Nov 2018
    Location
    Atlanta
    Posts
    16
    My Cars
    2001 740i
    Battery and ignition switch tests good. Voltage with engine running is 13.5 and ignition switch output on all three output terminals is the same after engine is started at 13.5 Volts as well.

    Can’t figure out why IKE test 9 voltage is so low!! The manual says that test 9 is battery voltage but could it be the generated bus voltage from the IKE gateway ? The manual says that gateway needs above 7 volts for reliable communication on the I and K busses

  4. #4
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    8,867
    My Cars
    99 840ci Sport Indv
    IKE Test 9 is the voltage from Terminal 15 - the voltage supplied when the key is in position I (accessories) - it doesn't measure I-Bus voltage, it measures a DC voltage presented to either the MID or the IKE depending on model. It is a strange reading, but probably nothing to worry about unless you have operational issues....
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


    My BMW Repair YouTube Channel
    My Current 840ci Sport Individual
    My Current 650ci Sport Individual
    My E31 Repair and Information Website
    My E38 Repair and Information Website
    My E63/E64 Repair and Information Website

    Chase - Heroes to a generation

  5. #5
    Join Date
    Nov 2018
    Location
    Atlanta
    Posts
    16
    My Cars
    2001 740i
    Lots of operational issues! The worst being intermittent trans fail mode. As well as tons of MID display issues. Where is terminal 15 ?

    john

    - - - Updated - - -

    Ps my model is a 740i sport model with winter package

    Vin WBAGG83481DN87322

  6. #6
    Join Date
    Nov 2018
    Location
    Atlanta
    Posts
    16
    My Cars
    2001 740i
    I tested the ign switch output when in ign switch position 1 (fist click clockwise) and it read battery voltage!

  7. #7
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    8,867
    My Cars
    99 840ci Sport Indv
    Tell us what problems you have - and then we will be able to give you better answers - when do you get TRANS FAIL-SAFE PROG? What other problems do you have?

    There are three basic voltage supplies (on all BMW models) Hot at all times (permanently live, not switched) - Terminal 15 (power supplied in key position I) - and Terminal 30 (power supplied when the key is in position II) - they do not relate to physical 'terminals' as such....
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


    My BMW Repair YouTube Channel
    My Current 840ci Sport Individual
    My Current 650ci Sport Individual
    My E31 Repair and Information Website
    My E38 Repair and Information Website
    My E63/E64 Repair and Information Website

    Chase - Heroes to a generation

  8. #8
    Join Date
    Nov 2018
    Location
    Atlanta
    Posts
    16
    My Cars
    2001 740i
    Thanks TIMM (btw chris kethan sends his regards and thanks for past help given)

    problems are intermittent ie about 2% of the time MID display on cluster works perfectly and when it does test 9 is always above 7volts

    sometimes display is blank but when sun is at a certain angle I can see MID info displayed

    sometimes display is full bright but “frozen” ie shift selector shows d when in park or vice versa. Also when this problem occurs the seat belt will show as plugged in when not plugged in or vice versa. Also in this problem mode the shift selector info will stay on when key removed

    sometimes especially recently the trans will be stuck in a gear and not shift, if the display is in bright mode it will show trans fail program mode on engine shutdown. Typically on restart trans works perfectly

    sometimes on start all lower cluster and MID including check engine light and low fuel light will stay on frozen until engine shutdown

    on all problems when the display is visible the test 9 voltage will read below 7 volts. When it works fine it will show more than 7 volts. There have even been a couple of times when everything “sort of” works and it will slowly but correctly show from p to n to d in the shift selector and slowly but correctly change from seatbelt connected and disconnected and then test 9 will be right AT 7 volts!!

    range of voltage readings on test 9 has stayed between 6.5 and 7.4 volts. Battery always is around 12.5 engine off and 13.5 engine running. Output voltage from ignition switch has always tested good with similar voltages.

    very strange and hard to trouble shoot.

    John

  9. #9
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    8,867
    My Cars
    99 840ci Sport Indv
    Did you check all the voltages from the ignition switch? There are four outputs from it - and any of them can cause problems.
    Timm..2007 E64 650i Individual Sport..1999 E31 840ci Individual Sport..ex owner of 2000 E38 740..1999 E38 740i V8 M62..1998 E38 735i V8..1993 E32 730i V8..1988 E28 518i


    My BMW Repair YouTube Channel
    My Current 840ci Sport Individual
    My Current 650ci Sport Individual
    My E31 Repair and Information Website
    My E38 Repair and Information Website
    My E63/E64 Repair and Information Website

    Chase - Heroes to a generation

  10. #10
    Join Date
    Nov 2018
    Location
    Atlanta
    Posts
    16
    My Cars
    2001 740i
    Yessir. I saw 3 thick wires and one thin trigger wire for the starter crank signal. The 1st wire was 12v in position one and all three thick wires showed 12v in position 2. The trigger wire got 12v in the spring opposed start position 3

Similar Threads

  1. 2001 740 IL engine fault help!!
    By jmac510 in forum 1995 - 2001 (E38)
    Replies: 6
    Last Post: 01-18-2011, 09:17 PM
  2. Thinking about buying a 2001 740... Need help!
    By shubbardman in forum 1995 - 2001 (E38)
    Replies: 18
    Last Post: 08-02-2009, 10:04 PM
  3. help!! 2001 740 i brakes
    By rodrigofome in forum 1995 - 2001 (E38)
    Replies: 1
    Last Post: 03-29-2008, 11:13 AM
  4. Coding issues .. help with IKE?
    By BayernKiwiBMW in forum 1996 - 2003 (E39)
    Replies: 1
    Last Post: 08-29-2007, 11:37 PM
  5. 2001 740 Navigaion Issues
    By Traveller in forum 1995 - 2001 (E38)
    Replies: 1
    Last Post: 12-11-2006, 10:14 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •