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E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

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  #226  
Old 08-10-2010, 09:25 AM
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bluebee bluebee is offline
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It was noted in this post that certain pins in the ABS control module harness connector are not connected to anything apparently.

To help out, here's a sorted list of the connections in the newer ABS control module harness connector:

Notice the eight apparently unconnected pins are: 14, 20, 22, 33, 37, 38, 39, & 7.

Pin 01 ABS/ASC control module, A52 = 4.0 BR --> X1106
Pin 01 ABS/DSC control module, A65 = 4.0 BR --> X1106
Pin 02 ABS/ASC control module, A52 = 4.0 RT --> X27, F108 25A
Pin 02 ABS/DSC control module, A65 = 4.0 VI --> X27 F108 50A
Pin 03 ABS/DSC control module, A65 = 2.5 SW/GN --> Pin 2 of M118 Precharge pump
Pin 04 ABS/DSC control module, A65 = 2.5 SW/BR --> Pin 1 of M118 Precharge pump, X1656
Pin 05 ABS/ASC control module, A52, X1170 = 2.5 BR --> X1106
Pin 05 ABS/DSC control module, A65 = 2.5 BR --> X1106
Pin 06 ABS/ASC control module, A52 = 2.5 RT/SW --> Pin 60 X10015, F30 25A
Pin 06 ABS/DSC control module, A65 = 2.5 RT/SW --> Pin 60 of X10015 F30 25A
Pin 08 ABS/DSC control module, A65 = 0.5 BL/WS/GE --> Pin 5 of B75 Yaw sensor
Pin 09 ABS/DSC control module, A65 = 0.5 BL/WS/GE --> Pin 2 of B75 Yaw sensor
Pin 10 ABS/DSC control module, A65 = 0.5 WS/BL/GE --> Pin 1 of B75 Yaw sensor
Pin 11 ABS/ASC control module, A52, X1170 = 0.35 WS/VI --> X183, Pin 20 of X6002
Pin 11 ABS/DSC control module, A65 = 0.35 WS/VI --> X183
Pin 12 ABS/ASC control module, A52 = 0.5 RT --> Pin 1 of B2 Left front speed sensor
Pin 12 ABS/DSC control module, A65 = 0.5 RT --> Pin 1 of X114, B2 Left front speed sensor
Pin 13 ABS/ASC control module, A52, X1170 = 0.5 BL/WS --> X376, Pin 2 of B4 Left rear speed sensor
Pin 13 ABS/DSC control module, A65 = 0.5 BL/WS --> Pin 2 of X376, B4 Left rear speed sensor
Pin 15 ABS/ASC control module, A52 = 0.5 BL/GE --> X113, Pin 2 of B1 Right front speed sensor
Pin 15 ABS/DSC control module, A65 = 0.5 BL/GE --> Pin 2 of X113, B1 Right front speed sensor
Pin 16 (without IKE) = 0.5 GE --> J5, Pin 16 of X11175
Pin 16 ABS/ASC control module, A52 = 0.5 GE --> Pin 1 of B1 Right front speed sensor
Pin 16 ABS/DSC control module, A65 = 0.5 GE --> Pin 1 of X113, B1 Right front speed sensor
Pin 17 ABS/DSC control module, A65 = 0.35 GR/SW --> J5, Pin 15 of X16, A2 Instrument cluster
Pin 18 ABS/DSC control module, A65 = 0.35 GE/WS --> X10184 --> X10184 --> Pin 24 of X991, A53 Control module, headlight vertical aim control
Pin 18 ABS/DSC control module, A65 = 0.35 GE/WS --> X10184 --> X1310 --> Pin 11 of X1312, A112 Control module, navigation
Pin 19 ABS/DSC control module, A65 = 0.35 GE/GN --> Pin 22 of X60004, A6000 DME control module
Pin 21 ABS/DSC control module, A65 = 0.5 SW/RT/GE --> Pin 6 of B75 Yaw sensor
Pin 23 ABS/ASC control module, A52 = 0.75 RT/WS --> Pin 62 X10015, F31 10A
Pin 23 ABS/DSC control module, A65 = 0.75 RT/SW --> Pin 62 of X10015 F31 10A
Pin 24 ABS/DSC control module, A65 = 0.5 GE/SW --> X18836
Pin 25 ABS/DSC control module, A65 = 0.75 WS/BL --> Pin 1 of X1654, B76 Pressure sensor
Pin 26 ABS/DSC control module, A65 = 0.75 BL/WS --> Pin 2 of X1654, B76 Pressure sensor
Pin 27 ABS/DSC control module, A65 = 0.5 SW/GE --> Pin 16 of X1869, A169 Switching center
Pin 28 ABS/ASC control module, A52, X1170 = 0.5 BL/RT --> X114, Pin 2 of B2 Left front speed sensor
Pin 28 ABS/DSC control module, A65 = 0.5 BL/RT --> Pin 2 of X114, B2 Left front speed sensor
Pin 29 ABS/ASC control module, A52 = 0.5 WS --> Pin 1 of B4 Left rear speed sensor
Pin 29 ABS/DSC control module, A65 = 0.5 WS --> Pin 1 of X376, B4 Left rear speed sensor
Pin 30 ABS/ASC control module, A52 = 0.5 BL/GN --> X377, Pin 2 of B3 Right rear speed sensor
Pin 30 ABS/DSC control module, A65 = 0.5 BL/GN --> Pin 2 of X377, B3 Right rear speed sensor
Pin 31 ABS/ASC control module, A52 = 0.5 GN --> Pin 1 of B3 Right rear speed sensor
Pin 31 ABS/DSC control module, A65 = 0.5 GN --> Pin 1 of X377, B3 Right rear speed sensor
Pin 32 ABS/DSC control module, A65 = 0.35 BL/RT --> X181
Pin 34 ABS/DSC control module, A65 = 0.5 BR/RT --> X1101
Pin 35 ABS/DSC control module, A65 = 0.35 GE/RT, X1746 --> Pin X10183 --> Pin 30 of X945, A80 EDC control module
Pin 35 ABS/DSC control module, A65 = 0.35 GE/RT, X1746 --> X10183 --> Pin 1 of X131- --> Pin 10 of X1312, A112 Control module navigation
Pin 36 ABS/DSC control module, A65 = 0.35 BR/GN/GE, X1746 --> X1123
Pin 39 ABS/DSC control module, A65 = 0.5 WS/GE --> Pin 3 of B75 Yaw sensor
Pin 40 ABS/DSC control module, A65 = 0.5 GE/BR --> X18835
Pin 41 ABS/DSC control module, A65 = 0.5 BR/SW/GE --> Pin 4 of X1653 B75 Yaw sensor
Pin 42 ABS/DSC control module, A65 = 0.75 SW/VI --> Pin 3 of X1654, B76 Pres
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  #227  
Old 08-30-2010, 11:08 AM
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bluebee bluebee is offline
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I keep getting asked (on other threads) why I had the ABS control module rebuilt when the initial diagnostic indicators were "114 Pressure Sensor Offset" and then "81 Einlassventil : vorne links (inlet valve, front left)". I understand why people ask as they are in the same boat I was in. They want to KNOW conclusively what part is wrong before throwing money at the problem. I did too. That's why it took me almost a year to come to the simple conclusion that, almost all the time, the problem is either a single sensor or the ABS control module wires.

Most people, including me, WANT desperately to trust the vaunted pinpoint accuracy of the diagnostic tools.

But the diagnostic tools can't tell you the truth in this situation. For clarification, I would point you to the final solution (post #163), which proved the problem was the ABS control module all along, not the pressure sensors or valves, which the diagnostic tools indicated.

I'll let Bill explain why the fancy schmancy diagnostic tools fail miserably to pinpoint the problem when you get the BRAKE DSC ABS trifecta which he attempts to explain in this thread.

Fundamentally, you need only a DMM and a thin set of wires for your home-made crystal ball - which turns out to be BETTER than all the diagnostic tools in the world (apparently).

Last edited by bluebee; 08-30-2010 at 11:12 AM.
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  #228  
Old 08-31-2010, 06:18 AM
repandpresent repandpresent is offline
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Trust me. I read all the threads regarding the ABS , Brakes and DSC lights. A lot of reading. I went to buy a DMM and the gauge wire that was recommended. I couldn't get solid connections. My last resort is to test at the wheels. Time to get really dirty. I guess I can clean my wheel wells while I'm at it.
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  #229  
Old 08-31-2010, 09:44 AM
orangedawg orangedawg is offline
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I have a 2007 e90 and I have these errors. Anyone know the pin outs that I should check for newer BMW's? I'm looking for something similar as mentioned in this forum that will tell me what pins I should use for each wheel sensor to check my sensors. Thanks!
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  #230  
Old 09-02-2010, 09:03 PM
m5roller m5roller is offline
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I'm having the same problem as several other with the diode check, I get no readings. But, I can check resistance. I see that one sensor has 50% more resistance than the others, but when I spin the wheel I see no fluctuation. I'm using the exact method described. This is obviously happening to more than one person. Since I'm getting good contact and can determine diode polarity by resistance, why won't the diode check method work? I've tried two DMMs in diode check mode to no avail and am getting a good connection as resistance measurements are repeatable.

Any ideas?

Thanks,
Trent
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  #231  
Old 09-03-2010, 08:41 AM
m5roller m5roller is offline
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To ensure that I'm getting a good signal for the diode check, I cut back the insulation on one of the sensors and probed the wires. Still no signal, resistance measurements the same at the probed wires and at the harness in the engine bay. Has ANYONE been able to reproduce the intial diode check step? There are at least three of us who have failed depsite following the same method.
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  #232  
Old 09-03-2010, 08:44 PM
m5roller m5roller is offline
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Update. For some unknown reason, the diode procedure started working, on about my 10th try (all sensors tested fine, for the diode check anyway). Must have been the DMM. Unfortunately, spinning the tires had no affect on resistance and produced no voltage. The ONLY change to the car was that I replaced a cheapo replacement sensor on the LR with the original part as the cheapo had much higher resistance measurements.

Guess I must assume the ABS module needs to be rebuilt.
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  #233  
Old 09-04-2010, 12:34 AM
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bluebee bluebee is offline
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Quote:
Originally Posted by m5ridero View Post
the diode procedure started working...Must have been the DMM
Thanks for taking the time & effort to give an update. I stayed out even though I see every post, because I had nothing to help you with. But I'm glad you got a diode reading finally!

Quote:
Guess I must assume the ABS module needs to be rebuilt.
I understand your dilemma.

There seem to be three kinds of BMW owners:
1. For every repair, they go to the dealer or indy (we're not that type)
2. If it's broken, they start throwing parts at it (don't laugh ... somewhere in this thread a supplier (EAC?) said they get orders for all four wheel sensors all the time)
3. When it's broken, they learn about the systems and subsystems in order to pick apart which are working and which are not; and then they diagnose until they've isolated the culprit; and only then, do they order the part.

I'm the third type (or at least I pretend to be). This type asks questions; refines the answer; learns about the system; and most importantly, this type buys tools and runs diagnostic tests in order to attempt to isolate the problem. This type does not blindly throw parts at the problem until it's resolved.

Unfortunately, in the case of the ABS control module, "the diagnostic type" has difficulty because we just do not have non-invasive diagnostic procedures that will conclusively prove it's the ABS control module acting up when you get the BRAKE DSC/ASC ABS trifecta.

Interestingly, I was told, from the very beginning, that if my sensors tested good, then it was the ABS ... but it took me almost a year to finally give up on trying to test the ABS control module to prove they were right (they were right after all).

Now ... there is an INVASIVE diagnostic procedure which has worked for the few who tried it. What you do is OPEN the ABS control module and LOOK for the larger steel wire lifting off the gold bondpad ... or the frustratingly thin gold wires leaning over and touching one another.

Those who have reattached the steel wire to the gold bondpad or who have isolated the gold angel hairs, have reported success.

The good news is that the rebuilders are willing to work on previously opened ABS control modules; so you don't have much to lose, especially if you just LOOK and then decide to send it off to the rebuilder.

Here's what I suggest as a procedure (heavily based on Bill's thread):
0. If you get the ABS BRAKE DSC trifecta ...
1. Check the wheel speed sensors with a DMM at the harness connector ...
2. If any one sensors tests bad, replace it (rarely, if ever, more than 1) ...
3. If you still have the ABS BRAKE DSC trifecta ... open the ABS control module ...
4. With a needle, probe the steel power wires (very carefully) to see if they are all still connected to their gold bond pads ...
5. With a needle, probe the gold angel-hair wires (extremely carefully) to ensure they are not touching one another ...
6. If you can, "fix" the wires (see the ABS autopsy thread for details).
7. If you can't fix the wires, now you can send the ABS control module out to the three recommended rebuilders ...

Choose your rebuilder (BBA/MM/ATE) in that order (ordered by quality & price as per the general recommendations of the users here).

Please report back your results (pictures are always nice). Good luck. Blue.
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  #234  
Old 09-04-2010, 11:21 AM
orangedawg orangedawg is offline
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I've got an 07 e90 328xi and was trying this out. From what I found in Bentley's, it looks like these are the pin outs for my car:

RF 6 and 18
LF 21 and 22
RR 19 and 31
LR 20 and 33

I did the diode test on my car using two different multimeters but don't under the results. They are:
Using one multimeter, all results for the sensors came up with a value of 688.
Using a different meter, results were 742.
What do these numbers mean? I thought it was supposed to be 1.7 or something. Any help?

I also did the mega (20M) test (testing one way and then reversing it and testing the other way) and the numbers are:
RF: 374 and 532
LF: 375 and 533
RR: 375 and 538
LR: 375 and 538.

Again, what do these numbers mean? Any help?

EDIT:

Put a new battery in one of my meters. Results now are:
On diode test, all sensors are either 683 or 684
On megaohm (20M) readings are 2.06 or 2.07 one way and 1.51 or 1.52 the other way.

All the numbers seem to be the same, but I don't understand the 683 numbers for diode test. Am I doing something wrong?

EDIT 2:

Put a new battery in my other meter as well. Numbers on it for diode test are all 732-734.
Mega ohm (the setting I used was 2000k) are 371 one way and 528-534 the other way.

BTW, on all my tests, when I do the diode test the reverse way, both meters give a value of 1, which I take to mean open or infinity.

Anyway, can anyone lend an opinion as to what my numbers mean? Am I doing this wrong?

Last edited by orangedawg; 09-04-2010 at 12:09 PM.
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  #235  
Old 09-04-2010, 11:34 AM
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540iman 540iman is offline
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I did a diagnostic test on my realtor's E39 touring. Carsoft said wiring to LR speed sensor was bad. Not bad sensor, not bad module, but said wiring itself. I tested his sensors with my VOM and all four sensors tested fine. I replaced the module and then scanned with GT-1 and it said steer angle sensor was out of calibration or some such. Turned wheel lock to lock while looking at output from the steer angle sensor and sure enough you could see that it was not balanced. We used GT-1 to balance, but error did not go away. Eventually took to my indy who has an Auto-logic scanner and he cleared the steer angle sensor. We had in fact balanced, but not able to clear error properly. Anyway, bottom line is that no scanner can detect a bad speed sensor from the module while they are still connected to each other. Also, despite the bad steer angle balance which did not show itself on the first scan, the module was in fact bad. Best analogy I can give you is say your stereo stops putting out any sound from the left channel. How could you possibly determine if the speaker itself is bad, the wires to the speaker are open or shorted, or if the amp itself has a bad channel if all are still connected? Don't tell me to plug in headphones cause we don't have that option in this analogy!! You must disconnect speakers from amp and then verify speaker, then look for shorted or disconnected speaker wires, then amp itself. You can not hook up a scanner way upstream at your OBDII port or your 20 pin socket and determine why sound will not come out the left channel. Got it? You could tell if the amp won't turn on (doesn't pull any current) or on/off switch has failed, but you can't determine whether a speaker is bad, wiring, or amp with all three still connected. You must test in between components to isolate. A four channel surround sound set-up is really an even better example.

Now, after replacing module for my realtor and coding, he was good to go...for 6 months and error came back. It had been perfect! I rescanned and it said RF speed sensor was bad. I tested it and the other three and sure enough the RF speed sensor had now gone bad. I had him order it and then I went to show him how I did the diode test. Low and behold, all 4 sensors tested "open" in both directions! How embarrassed was I??!! Use a small paper clip to insert into the module connector. Don't try and jam the meter test lead into the connector holes...the leads are too big. A paper clip (small one) works perfect. Plus, it is only straightened on one end and the remaining loop is good place to put your meter test lead. I repeated the tests over and over with key off, key on, and in every case, I found all his sensors open. I tried resistance setting rather than diode test and this is virtually the same test. Don't sweat it if you don't get same readings I do. I use a Fluke 77 which is a good quality VOM, but have heard of people who can't replicate my numbers. Remember, you are looking for an outlier. All of a sudden it hit me why I was getting all "open" readings (infinite resistance). Many paperclips-even the clear ones- are coated with a clear coating that acted as an insulator to my meter. Once I scrapped the paperclip with my thumb nail and I could see the clear coat flaking off, I knew I had been had!! Removed the clear coat and bingo, I got 1.707 volts in one direction and infinite resistance in the other. I showed him that on his bad sensor, he had dead short in both directions. Installed new speed sensor, cleared error, and he went on down the road.

Remember that a scanner such as Carsoft, GT-1, whichever CAN detect a module that has no communication with the rest of the system or some other problems, but it can't tell a bad "speaker" from bad wires to the speaker, or a dead channel in the amp. You must check the sensors themselves whether you use just conductivity test (should get about 6 mega-ohms in one direction and about 3 mega-ohms in the other-this means reversing the meter leads) or you use diode test. I always put key to position#2 which is all dash lights on and just before car`cranking, but this may not be necessary. Just why not?

Last edited by 540iman; 09-04-2010 at 11:45 AM.
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  #236  
Old 09-04-2010, 04:19 PM
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bluebee bluebee is offline
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Quote:
Originally Posted by 540iman View Post
All of a sudden it hit me why I was getting all "open" readings (infinite resistance) ... Many paperclips-even the clear ones- are coated with a clear coating that acted as an insulator to my meter.
Good observation Bill! We should warn people about that. I used very thin wires so I didn't have that problem. All the paper clips I had were way too large for the teeny tiny holes in the ABS control module harness connector.

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  #237  
Old 09-12-2010, 07:12 AM
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agent15 agent15 is offline
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I am thrilled to report that after simply removing the driver's side rear wheel sensor and cleaning it, I have gone a full week without the light trifecta returning. To be fair, I knew it was that particular one throwing codes from the PPI I had done at a dealer.
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  #238  
Old 09-12-2010, 07:59 AM
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540iman 540iman is offline
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With all due respect to the dealership, once again I will state that no GT-1, Autologic, or similar high end diagnostic meter can tell a bad sensor from a bad module UNLESS the sensors are disconnected from the module. I wonder if the dealers now have a device that they can connect to the main module connector with it disconnected from the module? Basney BMW in South Bend, IN. did not have one, but I guess that does not mean they are not available. To clarify, I have used my Carsoft software to direct me to the "bad sensor", but I then must follow-up with testing with a VOM to be 100% sure it is the sensor and not the wiring to the sensor, the connector, etc. Granted, even the lousy diagnostic equipment can tell you which channel is not acting correctly within the ABS system and then changing the sensor may have a pretty good chance of truly being the culprit, but if you think about it a minute; how would a diagnostic reader connected through the OBDII port or the 20 pin round under-hood connector know a bad sensor (open/shorted/faulty) from a shorted lead from the module to the speed sensor, an open, or whatever? Compare it to a surround sound system with many channels (5.1, 6.1 etc.) and one speaker is not working in your living room. You think any device can tell a bad speaker from bad wiring from a bad channel in your amplifier or a zillion other things if you leave everything hooked-up and try and diagnose through the amp? You need to check speaker, wires to speaker, and work your way back. You can just change a speaker and might get lucky, but to be 100% sure you need to hook speaker that is not working to another device and see if it now will play. You then go from there. That kind of process..

Glad to hear that you are good to go, but if it comes back (which I hope it doesn't) do not lose faith. There is information here by BB that will help you go further should you need to. All is not a mystery. BMW dealerships have told me that they often replace parts in the ABS system using some trial and error if they don't guess right the first time. They admitted to being fortunate that they have virtually endless parts to throw at a problem such that they will always get it right eventually. One tech said dealers often charge for all the parts they try and another admitted they will take that "used speed sensor" that does not cure a customer's issue and put it back in the bag and right back to the parts shelf as if it were never opened. They say it can be the single most frustrating job they routinely do or it can be the easiest-they never know. If the car has ever been in a wreck, the wiring that is otherwise generally not in question can be shorted or open in the strangest places! Steer angle sensors (yaw sensor) can also be a PITA as they will throw an ABS code when the sensor just needs calibration. They often fall off too or move on the suspension so they start reading screwy. This is a great, but complex system.
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  #239  
Old 09-12-2010, 02:38 PM
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agent15 agent15 is offline
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I understand the surround sound analogy, and I agree that no sound coming from a speaker needs more data to accurately diagnose the issue, though I (incorrectly?) believe that when discussing the DSC and/or ABS systems in these cars we are dealing with far more sophisticated hardware and electronics.

Do dealers use GT-1, Autologic or Carsoft? I was under the impression those were readily available to pretty much anyone who could afford them, and that dealerships had something proprietary to BMW, although that's purely conjecture on my part.
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  #240  
Old 09-12-2010, 03:01 PM
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540iman 540iman is offline
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Autologic roughly $14,000 Gt-1 ?? Problem is that a bad sensor is generally open or shorted. Sophistication really has nothing to do with the issue as say a short (just as an example) could be a short in that channel of the module, a short in the wiring to the sensor, or the sensor itself. If you break the connection somewhere, then you can tell if the short (or open) is upstream or downstream. The speed sensor is nothing more than a pulse generator and it is the loss of that pulse that causes the error in the first place. It can be as simple as a piece of metal stuck on the tip of the sensor, bad connection at pigtail, I/O side of the module....follow me? I'm just saying that it is a simple electrical fact that these diagnostic devices are great for diagnosing modules that stop communicating, or output of yaw sensor skews too far left or right of center, but basic failure of these simple sensors are not 100% successfully diagnosed by a scanner.

My first module failure said it was a bad LR sensor. I fell for it and replaced. Then it said RR sensor was bad. Swapped sensors and the error did not move. Turned out all sensors were fine and the module itself was cooked and acted differently depending on how hot it got. This is why I advocate that when a scanner says the RF sensor is bad, just check it with a VOM and you will know in about 2 minutes if it really is.
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  #241  
Old 09-12-2010, 03:14 PM
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agent15 agent15 is offline
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I understand what you're saying, but you've not clarified how the dealer's scanning tool, whatever make and model it is, said that the LR sensor was the one throwing the fault code. I would imagine there is a difference between a scanner pointing to a particular wheel's sensor as "open," as in a wiring issue or a failed sensor itself, versus the sensor telling the car's OBD system that it has an issue while still maintaining continuity to it.
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  #242  
Old 09-12-2010, 05:00 PM
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540iman 540iman is offline
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Quote:
Originally Posted by agent15 View Post
I understand what you're saying, but you've not clarified how the dealer's scanning tool, whatever make and model it is, said that the LR sensor was the one throwing the fault code. I would imagine there is a difference between a scanner pointing to a particular wheel's sensor as "open," as in a wiring issue or a failed sensor itself, versus the sensor telling the car's OBD system that it has an issue while still maintaining continuity to it.
I think you are saying that you understand, but are dismissing the thought process. The dealer's scan tool, Carsoft, or whatever scanners see many different symptoms that they don't like. Missing pulses, no pulses whatsoever, misshapen pulses as viewed on an oscilloscope, etc. They know what portion of the module they reside in. They can't tell the mechanic the cause, only the symptom. So, they identify the portion of the module that is whacked AT THAT MOMENT IN TIME. If the car were on a dyno and the wheels spinning, it would be better, but still not absolute because then it would possibly know if it is seeing pulses that the wiring is ok, but the sensor itself LIKELY bad. My Carsoft told me on my realtor's car that his sensor wiring was at fault when he actually had a bad sensor itself. I have no clue how it thought it could be so specific as to identify the wiring and not the sensor, but that is what it said. The same software, on my car, said it was the sensor itself-and it was after I confirmed by disconnecting and checking sensor with the VOM.

I am not discounting that the scanners can diagnose some faults (like communication faults) 100%. They can properly identify defective modules in many cases-say when a module is pulling no current whatsoever. Only the module can cause a symptom such as this. When it gets to the speed sensors themselves, they can be right still, but at a smaller percentage because of the nature of how the sensors generally fail. MOST (not all) go open. The cheaper scanners such as Carsoft assume the module itself works as long as it has communication. If a channel is dead, it will always diagnose as a bad sensor or sensor wiring. It will not return a bad I/O transistor in the module correctly. It will not diagnose a bad solder connection in the module as such. It will deliver a bad sensor message 100% unless the solder connection is not in the speed sensor signal path (again, like a communication error caused by a bad solder connection)-that it will get right. Talk to your Stealership tech. and they will tell you. Mark (aka EAC tuning Mark) has software very similar to what the stealer has and while he is working many of the bugs out of it, he will tell you that there is a big difference between accurately diagnosing the symptom and the actual cause. That can be trial and error. Many here will tell you of countless sensors diagnosed and replaced on to ultimately find it is the module itself.

I don't know if I clarified for you to your satisfaction. I can only tell you what is and why I as an electronic tech can justify it. Just do not believe that all bad sensor diagnosis are correct. People have spent countless dollars chasing supposedly bad sensors read by GT-1s down to Peakes.
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  #243  
Old 09-12-2010, 06:56 PM
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agent15 agent15 is offline
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Quote:
Originally Posted by 540iman View Post
The dealer's scan tool... can't tell the mechanic the cause, only the symptom. So, they identify the portion of the module that is whacked AT THAT MOMENT IN TIME.
I am not a mechanic, I do not have any first hand experience with using any of these particular pieces of hardware or software, and I am certainly not trying to discount your experience or knowledge on this subject. I can only regurgitate what I was told by the dealer who performed the PPI, which is there was a history of a fault code at the LR wheel sensor.

The PO told me the light trifecta issue had happened to him "two or three times and that it cleared itself the next time the car was turned on." The issue did not occur on my test drive of the vehicle, at the dealership during the PPI, nor at any time during the three hour drive home three days later when we exchanged money for keys. It did happen to me a couple of days later, and just as the PO said, cycling the ignition cleared the lights.

All that said, I definitely feel fortunate that I was able resolve the issue, at least temporarily, by a ten minute procedure at zero cost. I have asked the service manager at the dealership to send me the list of actual codes pulled during the PPI, since they're not doing either of us any good sitting in his files when we're geographically separated by two hundred miles. I will be happy to share them once they're in my hands.
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Old 09-13-2010, 03:08 AM
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540iman 540iman is offline
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Code "history" certainly helps. If I were a scan tool "expert" I would be building and selling them myself! Good mechanics and good technicians are a lot like Doctors in that they use many pieces of "symptom" to assign a cause. For example, shorts or opens can be intermittent, but generally do not display "heat-related" tendencies unless they may involve solder or very precise wire movement. When I hear of codes coming and going (clearing by themselves and then re-curring) MY experience points to a module. The sensor usually are good or bad. This includes metal shavings on sensor. Metal stays there until removed. Time driving relative to heat can be different than type of driving-stop and go creates more heat than 3 hour drive say on freeway. History of LR sensor errors that clear usually points to bad module with lose solder connection on module board at LR channel. History is your friend!
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Old 09-13-2010, 06:48 AM
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bluebee bluebee is offline
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I should repeat that scan tools told me three different (bogus it turns out) faults (previously mentioned in this thread).

I don't remember the actual BMW codes thrown (it's in the aforementioned thread), I think it was 41 and 81 but I'd have to check. One was the hydraulic pressure sensor, another was the wheel sensor, and another (which failed me for my smog even though it was bogus) was the official-sounding "P0500 wheel speed sensor") ...

NONE of those three bogus faults was "real".

By real I mean the sensor itself was fine. The problem, as Bill says, all along is that the diagnostic tool was, in effect, telling me the symptoms - but not the fault.

It should be enough to note that rebuilding the ABS control module cured all the faults (I had to manually clear the P0500 but it never came back). It has been about 9 months since this so I think Bill's explanation has stood the test of time, at least with me.
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Old 09-13-2010, 07:04 AM
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bluebee bluebee is offline
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Quote:
Originally Posted by agent15 View Post
...history of a fault code at the LR wheel sensor.
Hi Agent15,
If this were my bimmer, and if someone told me I had a "history of a fault code" in my LR sensor, the FIRST thing I would do is open the hood and put my DMM leads on pin 13 and on pin 29. If the readings were bad (see chart below), I'd check the sensor at the wheel. If the readings are still bad, I'd replace the sensor. (Notice there's no need for fancy schmancy test tools.)

Now, if the readings were good, then I'd be in a quandary (presumably like you are in now). It could be my sensor was intermittent, or it could be the ABS control module is intermittent.

The "history" here is that almost everyone has an ABS control module that is intermittent to varying degrees before the trifecta stays permanently. There is NOT a reliable history of sensors being intermittent (AFAIK).

That combined history from multiple vehicles would tell me a lot.

Quote:
Originally Posted by agent15 View Post
The PO told me the light trifecta issue had happened to him "two or three times and that it cleared itself the next time the car was turned on."
Same thing happened to me (if you look in post #48 you'll see I had one light, then two, then three, and it would, at first, go away when I restarted the car). This happens to a LOT of people.

So far, the intermittent and disappearing trifecta has happened to very many people here, most who have reported that the solution was to repair the ABS control module (many people don't report the solution so you have to throw out that data).

Quote:
Originally Posted by agent15 View Post
The issue did not occur on my test drive of the vehicle, at the dealership
It's intermittent.

Quote:
Originally Posted by agent15 View Post
It did happen to me a couple of days later, and just as the PO said, cycling the ignition cleared the lights.
It's intermittent. And it's (originally) cleared by cycling the ignition.

Quote:
Originally Posted by agent15 View Post
I definitely feel fortunate that I was able resolve the issue, at least temporarily, by a ten minute procedure at zero cost.
My intuition tells me you'll get the trifecta soon enough again but I hope, for your sake, that the solution is permanent. I do realize the anguish of not being able to definitely ascertain the fault location when the ABS control module is concerned. As I've said many times, that's why it took me nearly a year to finally bite the bullet and "throw parts" at the problem by having my ABS control module rebuilt by ATE for $150 (includes shipping costs).

BTW, when you DO get the intermitent trifecta, are the speedo and odo and tripmeter adversely affected?
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Old 09-13-2010, 07:05 AM
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It sounds like both of you are trying to tell me I'm wrong, albeit politely. Again, I can only relay my personal experience with the issue which is: PPI > code > zero-cost repair based on code.

Should the issue recur and the resolution require anything be done with the ABS control module, I promise to report back.
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  #248  
Old 09-13-2010, 07:15 AM
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bluebee bluebee is offline
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My car is currently in the shop and I have no access until Monday. By then, I will provide pictures.
I was re-reading parts here to help someone.

You fixed the car in July but we never saw the pictures.

It would help others because your harness connector is different than mine.
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  #249  
Old 09-13-2010, 05:42 PM
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540iman 540iman is offline
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Quote:
Originally Posted by agent15 View Post
It sounds like both of you are trying to tell me I'm wrong, albeit politely. Again, I can only relay my personal experience with the issue which is: PPI > code > zero-cost repair based on code.

Should the issue recur and the resolution require anything be done with the ABS control module, I promise to report back.
No, we are telling you the experiences we have encountered to try and help others who face the same thing, as well as explain- as best we can- possible reasons for the inability of every diagnostic device that I know of personally having misdiagnosed this error "area"....the trifecta brake lights. No subject likely has as much coverage as it is very frustrating for the average DIY'er, which after all is what brings most of us here, to diagnose using all the standard devices available to not just us, but to indys and techs we have gone to for help.
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Old 09-17-2010, 05:59 PM
jeffstri jeffstri is offline
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This is my first post here. I apologize for it's length and I hope it's taken in the spirit intended (intended to be helpful).

I have a '01 e38 (740il) which has the same ABS/DSC system that many of your e39s have (DSC5.7). I found this thread searching for some insight into my ABS problem: the dreaded brake light trifecta with fault codes that I haven't seen reported here (more about that another time.)

I've perused the entire thread twice and one observation I'd like to make is that there seems to be a misunderstanding of what fault codes mean and how they should be used. Fault codes are not intended to be diagnoses. Whatever scan tool you use, a fault code(s) rarely leads to a solution without more testing. I suspect that the misunderstanding comes in part from the way consumer scan tools such as the OBD scanners Autozone uses, the Peake tool, and Carsoft are marketed.

To give an analogy that's meaningful to me, given my healthcare background, a fault code is like an abnormal blood test result. For example, an abnormally increased white blood cell count (a "fault code") suggests an infection (although it could be caused by other things, and even be "normal"), but it doesn't tell you anything about the site of the infection (e.g., lungs, abdomen, etc) or the organism that has caused the infection, both of which are necessary to treat the infection properly. More information and tests are needed.

Similarly, a wheel sensor fault is not intended to mean that the sensor itself is defective and should be replaced without further testing. It means that the control unit (the DSC module) that monitors the sensor is reporting that it had faulty (or no) communication with the sensor. If the fault code text from a scan tool such as Carsoft is overly specific (e.g., the wiring is faulty), that's probably inaccurate and misleading, and not the same fault description that BMW would use .

The software a BMW dealer uses to read fault codes (INPA, GT1/DIS) also allows measurements (e.g., brake pressure) and activation of various components (e.g., ABS solenoids, pre-charge pump). DIS also provides diagnostic algorithms and tests for translating fault codes into a diagnoses. Modules can be calibrated, coded, and programmed with DIS, SSS/Progman and NCS Expert. WDS provides wiring diagrams, pictures of component locations, module pinouts, and electrical troubleshooting procedures.

INPA, DIS, SSS/Progman and NCS Expert can be be found on the internet, along with excellent instructions for installation and use (http://forums.bimmerforums.com/forum...play.php?f=233). All you need is a computer (preferably a laptop) and a diagnostic interface/cable set; I use an "INPA/Edaibas" set that I bought from China on ebay for about $35. WDS can be accessed directly online http://www.bmw-planet.com/diagrams/r...9new/index.htm)

All the above is a preamble to defending the process that agent15 went through and the likelihood that he has in fact solved his problem. What he did was entirely consistent to what is recommended in the WDS:



It's also important to note that reliance on the diode/resistance tests advocated in this thread would probably have indicated his wheel sensor was not the problem and may have led to unnecessary repair/replacement of his DSC module.

Last edited by jeffstri; 09-17-2010 at 06:15 PM.
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