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Discussion Starter · #1 ·
Well the history on this old 7. Got it in 2010 from a guy who claimed nothing major was wrong with the car. had an electrical issue that keeps draining the battery. Still have not been able to fix that issue.

Main problem.
About two years ago i got it brand new tires. in the process they broke one of my wheel speed sensors wires. The speedometer stopped working. took a look at all four wheel speed sensors and noticed they all needed help. I replaced them. Speedometer did not come back online. has not worked and therefore have not been able to pass inspection so i cant drive it. has been parked while i decided/saved for repairs. Have not been able to save much due to other projects/priorities.

Now im about at the end of my wits with trying to fix this myself. i dont have any experience repairing BMW's but im ok with regular vehicle mechanics. im not a full fledged mechanic but im mechanically inclined so i need someone to help bridge the gap of my ignorance.

Any help is greatly appreciated. Please dont respond with take it to am mechanic as that is not an option for me. I bought the BCables.com cable to use GT1, DIS, TIS, SSS, INPA...etc but i have not been able to get it to work with the car. The car turns on and drives and its slowly getting worse. windows are getting stuck sluggish, low beams are no longer working.... I need help to bring this car back from the dead. i fnot i will be forced to let it go believeing it could have been a good car if i were smarter. thanks for any help folks.
 

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If you have a battery drain, chances are your battery is no longer sufficient to run the vehicle properly. This car is very particular about voltage. That may or may be your window and light issue. Go to Harbor Freight and pick up a $5 multimeter and find your drain:

http://www.meeknet.co.uk/e38/E38_Battery_Drain.htm

If you replaced your wheel speed sensors with cheap aftermarket sensors, those rarely work. OEM is Siemens or Bosch. Your speedo is monitored by the drivers rear wheel speed sensor.

When running diagnostics on this car, the cap on the port you are NOT using must be attached for the other to work. So, if you are plugging into the 20 pin port under the hood, make sure the OBDII port, next to your broken cupholder, has the cap on it.

You should list the year of your car in your info. There are variables in this info depending on the year.
 

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Discussion Starter · #3 ·
I have a 1997 BMW 750il. Manufactured 05/96 750iAl this is what is on the VIN tag. Every other window is working properly. Voltage on the battery showed good during the software hookup. i recently had the battery load tested at the "Interstate Battery Store". I have to apologize for not being more specific in the original post.

The Drain is due to the alarm system being triggered randomly. The lights start to flash when the car is locked. in order for me to prevent this from happening i have to leave the car unlocked... Always unlocked. so i have read that this is due to the hood alarm sensor being triggered but was unable to find more info on that. This may or may not be the issue. I do not know how to test this since it is random and does not happen when i try to reproduce the alarm trigger.

the wheel speed sensors were in fact ebay sensors. I was unaware that they HAD to be Bosch or Siemens. Well thats ****ty but should have seen that coming... so now how can i check for sure that the sensors i installed are actually not working? Can i perform a test on them? these two things are ultimately the main issues. with no speedo no inspection.... ergo no driving... the drain sucks but does not necessarily park the vehicle. I can try to disarm the alarm to prevent the drain or it would be IDEAL if I could repair this fault. Any ideas? again sorry for the vague OP it was after four hours or so of struggling with some troubleshooting software, just didnt occur to me that i needed to be more specific. Burnt brain i suppose
 

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To pass inspection, I would strongly suggest buying a Siemens sensor for the rear drivers side. Some aftermarket do work on and off but most never work at all. Here is the best link you will find on this issue on any forum:

http://www.bimmerfest.com/forums/showpost.php?p=4205801

You can try a couple of things on the alarm. The hood sensor is indeed a common culprit. It is an 'Open circuit' sensor, meaning the circuit closes if the hood opens activating the sensor. This mean you can simply unplug the sensor. If the problem never comes back, the sensor is probably your culprit. When you lock the doors with the fob, hitting the button a second time disables the tilt and motion sensors. I would do this if unplugging the hood sensor does not stop the issue.

You said 'windows' so I thought all were slow. Lights, including low beams, are handled by the Light Control Module. Hopefully you have had no water issues inside the cabin. The LCM is behind the kick panel in front of the passenger door.
 

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Discussion Starter · #5 ·
i sure hope water has not been getting in. the windshield does need to be re-seated and the gasket material could be replaced. i have not seen any water nor does it smell like old water in the cabin. everything seems ok inside, apart from the cosmetic things that are starting to accumulate. i bought the plastic inserts to replace old and worn ones but they were too small. im sure they are for some interior parts just not the a pillars where i need mine. so im looking at more of them so that i can fix the interior parts that are starting to fall off. im checking out the siemens sensors on OEMbimmerparts.com seems they are on sale for 101$. Guess I should buy all four. since funds are scarce i'll start with the Rear,ill replace both the rear sensors then work my way up to the front ones later. thanks for the heads up on that. i thought the computer needed to be reset in order for the speedometer to come back online. i never would have suspected the New sensors i got were not ever working. my ignorance is shining a hole in my pocket. hopefully i can repair this and get back on the road at least.

the low beams are out though. dont know how or why, they worked a week ago and there has been no rain since then. i thought maybe because i connected the bcables module i screwed something up. ill check out the fuses and the LCM to see what i can find out. high beams work with noproblems just low beams are out and i get the message to check the low beams on the dash screen.
 

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If you can't get the alarm to stop triggering...stop arming the car when you lock it. You can do this by locking the vehicle manually from one of the passenger doors. Make sure the battery is sufficiently charged or that your driver's door lock cylinder and trunk cylinder works in the MANUAL positions.

The car is armed (DWA) when the car is locked with the remote or from the driver's door...and goes into double lock. But if you lock the car from the central lock button on the CENTER CONSOLE...or manually push the door pins down...or if you have auto lock @5MPH activated...the car only single locks but is not armed.

So, since the driver's door has an anti lockout feature that won't let you lock it when it's open...close the driver's door, then from one of the other passenger doors, press the central lock button on the center console or each door pin. The car will be locked...but the alarm won't be armed. And you can unlock the car manually from the driver's door...or using the remote key buttons (if you have electrical power). But again, if you don't have power...make sure you can get into the trunk & cabin so that you can open the hood or trunk & supply power to the battery.
 

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Discussion Starter · #7 ·
the 750il has only the main switch by the center console arm rest. when i hit the button its set to lock all doors and when you hit it again it un-locks them. ill try to mess with the manual locking method to see if i can get the lights to stop blinking. i have not seen it do it much since i put in the freshly tested battery. it only happened twice while i was messing around with it. i just bought the OEM Siemens sensor so ill tackle that maybe next weekend and see if i can get the speedometer back. then work my way up on the car.

has anyone ever used the Bcables software successfully on an e38? or know of someone who has. ill dig a little more on the forums to see what i can find. thanks for ur help thus far guys.
 

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Discussion Starter · #8 ·
Got the speedometer working today. I recieved the sensor yesterday bought from one of the recommended stores from BF. Thanks to Mayorchuck for the insight! Man I had no idea how to determine if the sensor I installed was bad from the beginning. It was a brand new sensor so I figured it would function. It did not and caused me my u ch confusion. Finally able to get the inspection.

Now much new issue.... my lowbeams worked for a few minutes and then cut off. I don't know why. I looked at the fuse box and did not find any burnt fuses. If it was a fuse there would be few ways they would only work for a little while. Any ideas would be great, thanks. I'll browse the forum in the meantime.
 

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Glad you got it going. The lights are handled by the Light Control Module. It is located behind the trim panel in front of the passenger door. It is known to get wet with leaks from the sunroof drains and sometimes they just go bad. There are usually more symptoms when they start to crap out though. I would try a few things before inspecting it since it is a little work to get to. First, make SURE your battery is good. This car will throw fits with low voltage. The other thing I would try is a battery nap. This often corrects odd glitches in the system. If you have NAV, wait for the light to go out and then remove both battery cables. Wait 10 minutes or so and then touch the cables together for a minute before putting them back. If you have a battery charger, just remove the cables and charge the battery overnight. This will accomplish both.

Here is the LCM:

 
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