Results 1 to 17 of 17

Thread: 850ci eml/check engine light - solved

  1. #1
    Join Date
    Nov 2014
    Location
    Nevada
    Posts
    77
    My Cars
    1993 740i-6 speed

    850ci eml/check engine light - solved

    Hello, my 1997 850ci recently started doing something strange. The eml light will come on and the car will run slow in the 6cyl/limp mode. I turn the car off and on and the eml goes away and only a check engine light is left. Itís always ran very smooth and has no noticeable issues even with the check engine light on. The check engine codes that came were:
    P1592: throttle valve 2
    P1270: control module self test
    P0600: serial communication link.

    This is the second time this has happened, the first time the check engine went away on its own. Iím thinking it may have to do with the throttle bodies and plan on cleaning those. Any recommendations, possible causes, and tips would greatly be appreciated. Thanks
    Last edited by Jormotors; 07-26-2018 at 02:24 AM.

  2. #2
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    6,522
    My Cars
    99 840ci Sport Indv
    I think you have answered your own question - time to refurbish the throttle bodies!
    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 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

  3. #3
    Join Date
    Nov 2014
    Location
    Nevada
    Posts
    77
    My Cars
    1993 740i-6 speed
    Great, is there any certain procedure for refurbishing the throttle bodies?

  4. #4
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    6,522
    My Cars
    99 840ci Sport Indv
    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 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
    Jun 2008
    Location
    N/A
    Posts
    2,826
    My Cars
    TT Cayenne / SC 850
    Quote Originally Posted by Jormotors View Post
    Great, is there any certain procedure for refurbishing the throttle bodies?
    I can rebuild your throttles and bring them back to factory spec, not just clean them up.
    PM me if interested.

  6. #6
    Join Date
    Jan 2005
    Location
    Japan
    Posts
    42,981
    My Cars
    11/88 E32 750iL+98 E36M3
    under reference data I also have the data for testing, see DK input details on my website.
    SHOGUN'S TRICKS AND TIPS FOR THE SEVEN SERIES
    http://twrite.org/shogunnew/topmenu.html

  7. #7
    Join Date
    Nov 2014
    Location
    Nevada
    Posts
    77
    My Cars
    1993 740i-6 speed
    Thanks!!

  8. #8
    Join Date
    Sep 2008
    Location
    Santa Barbara
    Posts
    2,563
    My Cars
    91 Dinan860 & 91 850 6sp
    Do yourself a favor and have Dragon850 (Ed) do it. Even I learned that ...

  9. #9
    Join Date
    Feb 2007
    Location
    UAE
    Posts
    629
    My Cars
    SL300-24, 750iL, 633CSi
    But he has an M73, correct me if im wrong, they don't require a rebuild like the M70 ones
    "Understeer is when you hit the wall with the front of the car, Oversteer is when you hit the wall with the rear of the car, Horsepower is how fast you hit the wall, Torque is how far you take the wall with you."

  10. #10
    Join Date
    Jun 2008
    Location
    N/A
    Posts
    2,826
    My Cars
    TT Cayenne / SC 850
    Quote Originally Posted by spitfire980 View Post
    But he has an M73, correct me if im wrong, they don't require a rebuild like the M70 ones
    Oh crap, yeah it is M73... did not notice that!
    Those throttles are not rebuild able, only solution is to get a low mileage set. I have one.

  11. #11
    Join Date
    Jan 2005
    Location
    Japan
    Posts
    42,981
    My Cars
    11/88 E32 750iL+98 E36M3
    No, unfortunately not possible to rebuild the Siemens DK's, good that spitfire980 noticed it.
    On the other hand, the Siemens DKs used are not too expensive, last week I was searching for 1 for a buddy for his E38 750 with M73. Found a lot, and prices were not bad, some less than $150
    SHOGUN'S TRICKS AND TIPS FOR THE SEVEN SERIES
    http://twrite.org/shogunnew/topmenu.html

  12. #12
    Join Date
    Nov 2014
    Location
    Nevada
    Posts
    77
    My Cars
    1993 740i-6 speed
    Update: I replaced my #2 throttle (drivers side) with a known good used throttle and the issue stayed the same if not got worse. Iím still getting same codes as before including p1572(throttle 2 potentiometer). Iím starting to think this may be an electrical issue because the car seems to run fine before the eml triggers and goes into limp mode. If I floor the car or drive even more than 3 miles the light will come on. I switched mafs and this made no difference. I did not find any vacuum leaks and spark plugs+filters were done recently. Iím a bit lost here because I feel if this was a true running issue such as bad spark, vacuum leak, or fuel issue that I wouldnít get a code for throttle 2 specifically, also battery voltage was good. Maybe bad EML? Keeping in mind this is a 1997 with the m73 Iím having a bit more trouble finding history of other e31ís with these codes. Any help would greatly be appreciated.

  13. #13
    Join Date
    Nov 2014
    Location
    Vena, Sweden
    Posts
    117
    My Cars
    1992 BMW 850ia
    Check your ignition system on the failing side or both, such as cables, distributors and ignition coils. Also the fuel system, pumps and pressure regulators.

  14. #14
    Join Date
    Feb 2010
    Location
    Hampshire UK
    Posts
    6,522
    My Cars
    99 840ci Sport Indv
    You are getting error messages from two places -

    The EML is complaining that the two potentiometer signals from the throttle valve on Bank 2 are not plausible - there are two potentiometers inside the throttle body and the signals must track each other, and if they don't then the EML will complain. As you have changed the throttle body and the error persists then the problem must be with the wiring between the throttle and the EML - or the EML itself. On the E38 this problem is seen when the EML gets waterlogged - so well worth checking that.

    The ECU is bunging up error P1270. P1270 is not 'control module self test' - on the M73 it is 'Mass Air Flow Sensor Bank Comparison Plausibility'. The ECU is complaining that one bank is slurping in a lot more air than the other side - and that doesn't make any sense as the two banks are joined by the crankshaft! So, is it that one MAF is completely mis-reporting the airflow, or, is the throttle body just not opening correctly? Well, as you have changed the throttle body then it would seem more likely one MAF is at fault.

    Fortunately, on the M73 you can use INPA to watch the live data and actually see the mass airflow and the throttle angles. So, that is where I would start - more info here:

    https://www.meeknet.co.uk/E38/Diagnostics.htm
    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 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

  15. #15
    Join Date
    Nov 2014
    Location
    Nevada
    Posts
    77
    My Cars
    1993 740i-6 speed
    Quote Originally Posted by Timm View Post
    You are getting error messages from two places -

    The EML is complaining that the two potentiometer signals from the throttle valve on Bank 2 are not plausible - there are two potentiometers inside the throttle body and the signals must track each other, and if they don't then the EML will complain. As you have changed the throttle body and the error persists then the problem must be with the wiring between the throttle and the EML - or the EML itself. On the E38 this problem is seen when the EML gets waterlogged - so well worth checking that.

    The ECU is bunging up error P1270. P1270 is not 'control module self test' - on the M73 it is 'Mass Air Flow Sensor Bank Comparison Plausibility'. The ECU is complaining that one bank is slurping in a lot more air than the other side - and that doesn't make any sense as the two banks are joined by the crankshaft! So, is it that one MAF is completely mis-reporting the airflow, or, is the throttle body just not opening correctly? Well, as you have changed the throttle body then it would seem more likely one MAF is at fault.

    Fortunately, on the M73 you can use INPA to watch the live data and actually see the mass airflow and the throttle angles. So, that is where I would start - more info here:

    https://www.meeknet.co.uk/E38/Diagnostics.htm
    Thanks for the advice, I used a high end code reader and did a data log while driving, my maf sensor voltages were good and my throttle positions were equal the whole time as well. I switched MAFS to see if it made any difference in the issue but it did not. Next i'm going to check out my EML and see if i can find any faults with it inside. If that doesn't work I will have to continue on doing maintenance in hopes of finding the issue. I'll let everyone know when i figure it out.

  16. #16
    Join Date
    Nov 2014
    Location
    Nevada
    Posts
    77
    My Cars
    1993 740i-6 speed
    SOLVED: This is a bit embarrassing but the problem was exactly what it said to be, throttle #2. What I did not realize was that the intake manifold crosses over meaning the throttle on side 2 is actually the throttle that controls bank 1 so i had replaced the wrong one. I threw in the used throttle I had on the other side and everything works perfect now. It took me a while to realize this but at least I did a lot of maintenance and have a working car now. Thanks for all the help and suggestions.

  17. #17
    Join Date
    Dec 2006
    Location
    Sunny Cali,
    Posts
    8,455
    My Cars
    6.5 second 69 Camaro
    For what it's worth, everything up top controls the opposite side.

Similar Threads

  1. Rough Idle/Check Engine Light - solved
    By chazsandiego in forum 1988 - 1994 (E32)
    Replies: 4
    Last Post: 05-03-2018, 12:26 AM
  2. DSC, EML & Check Engine Lights On
    By rpg in forum 1996 - 2003 (E39)
    Replies: 28
    Last Post: 05-03-2014, 10:30 AM
  3. Check Engine Light, EML, & ASC same time!
    By PGillPro in forum 1999 - 2006 (E46)
    Replies: 27
    Last Post: 02-11-2013, 12:39 AM
  4. Check Engine Light and Code 1221: SOLVED!
    By GEN3RIC in forum 1992 - 1999 M3 (E36)
    Replies: 4
    Last Post: 07-02-2010, 08:02 PM
  5. Check Engine light solved - for winter people
    By Glenn 328is in forum General BMW sponsored by Intercity Lines
    Replies: 4
    Last Post: 03-12-2002, 05:24 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
  •