ABS/BRAKE/TRACTION CONTROL light on

[seven11]

2001 BMW 740iL

i have the ABS/BRAKE/TRACTION CONTROL light on

scanner said "PRESSURE SENSOR, LINE" FAULT CODE 51

changed the sensor and reset the code and nothing changed

what could it be? ABS MODULE? i dont want to start throwing money at this car as this is my beater car but i would want everything to work. so i need your help guys.

here are a couple pictures of the car, its really clean

[mgalvin1]

My abs lights have been on for over a year now and they can stay on ! until an ABS DSC ECU comes up at a reasonable price , BMW want about £800.00 for the unit and I can get one from bosh for £400.00 but that's still to much for me ! My car drives fine with this faulty part aswell , I just keep an eye out on eBay for one to come up at the right price . I have been told that when this part goes wrong it can bring up all sorts of fault codes :S . Good luck

[purplecty]

Its definitely the ABS Module... Look up module masters or bba-reman. They can rebuild for a great price and give warranty...

[Timm]

If the fault lights only come on once the car starts moving - then the fault will be the pre-charge pump. Have a full read of this:

http://www.meeknet.co.uk/e38/ABS/Index.htm

The pressure sensor error is not a fault with the sensor, but is the failure of the brake pressure to rise when the pump is commanded to run.

[stritarja]

If the fault lights only come on once the car starts moving - then the fault will be the pre-charge pump. Have a full read of this:

http://www.meeknet.co.uk/e38/ABS/Index.htm

The pressure sensor error is not a fault with the sensor, but is the failure of the brake pressure to rise when the pump is commanded to run.

Timm,

It's important to know that a faulty pre-charge pump can cause this, but it's a mistake to generalize and assume that it's the only, or even most common, cause.

I had the same symptoms (code 51 and fault lights only after the car started moving) and it turned out to be a faulty DSC module. I didn't replace any parts until I had fully run through all the DIS diagnostics, and what I eventually found was that the apparent brake pressure with no pressure on the brake pedal, which should have been +/- 2 bar, fluctuated between 0 and 292 bar. I found that I could reproduce the fluctuations by wiggling the wiring harness connector to the DSC module. The continuity of the wiring harness checked out ok, but I was able to to show that the internal ground connection for the pressure sensor within the DSC module was faulty. Rebuilding the DSC module (BA-reman) fixed the problem.

[79howard]

Its definitely the ABS Module... Look up module masters or bba-reman. They can rebuild for a great price and give warranty...

+1-I did module masters with my former 01 740il and for, I think, $200 they fixed it. Very simple R&R and fast turn around time.

Much better than paying $800 for a new module and than paying the dealer $200 to program it to the car.

[seven11]

well today when i started the car the ABS light was on, then i started driving and the light turned off,

i wanted to see if the traction control turned on and off so i pressed the DSC button and it turned off by showing the Traction control triangle in a circle, i thought the sensor fixed it.

then i pressed the brakes and the ABS light came on,

then i continued driving and the ABS light turn off again.

i wanted to see if i had abs so i braked really hard and the ABS light came on and just stays on now.

before the sensor change the ABS/TRACTION CONTROL light was always on, could it be that i had a faulty sensor and something else?

stritarja, that's the fault code i got and my brake pressure was 290

So, is this still the ABS module? or the DSC module?

now the ABS light just stays on.

cold, warm... the light is on

[stritarja]

+1-I did module masters with my former 01 740il and for, I think, $200 they fixed it. Very simple R&R and fast turn around time.

Much better than paying $800 for a new module and than paying the dealer $200 to program it to the car.

A new Bosch module is only $431 from EuroParstDirect
and coding should only be about $100, free if you know someone with DIS.

DSC module rebuild by BBA-reman is only $99 with free shipping both ways if you buy it on ebay.

well today when i started the car the ABS light was on, then i started driving and the light turned off,

i wanted to see if the traction control turned on and off so i pressed the DSC button and it turned off by showing the Traction control triangle in a circle, i thought the sensor fixed it.

then i pressed the brakes and the ABS light came on,

then i continued driving and the ABS light turn off again.

i wanted to see if i had abs so i braked really hard and the ABS light came on and just stays on now.

before the sensor change the ABS/TRACTION CONTROL light was always on, could it be that i had a faulty sensor and something else?

stritarja, that's the fault code i got and my brake pressure was 290

So, is this still the ABS module? or the DSC module?

now the ABS light just stays on.

cold, warm... the light is on

Was your brake pressure 290 without your foot on the pedal?

There is only one ABS/DSC control module.

Initially my fault lights only came on after driving, later they came on all the time.

Check the WDS for the pressure sensor, pre-charge pump, and ABS/DSC module pin-outs, and back-probe the pressure sensor, pre-charge pump, and DSC module connectors to check the continuity and signal voltages. In my case, I found the ground connection for the pressure sensor (pressure sensor pin 2, DSC module pin 25) was bad. The continuity between the pressure and the DSC module was fine, but by wiggling the DSC module connector I could tell that the internal connection within the DSC module between the pressure sensor ground (pin 25) and the external ground connection (pin 5) was the problem.

[seven11]

A new Bosch module is only $431 from EuroParstDirect
and coding should only be about $100, free if you know someone with DIS.

DSC module rebuild by BBA-reman is only $99 with free shipping both ways if you buy it on ebay.



Was your brake pressure 290 without your foot on the pedal?

There is only one ABS/DSC control module.

Initially my fault lights only came on after driving, later they came on all the time.

Check the WDS for the pressure sensor, pre-charge pump, and ABS/DSC module pin-outs, and back-probe the pressure sensor, pre-charge pump, and DSC module connectors to check the continuity and signal voltages. In my case, I found the ground connection for the pressure sensor (pressure sensor pin 2, DSC module pin 25) was bad. The continuity between the pressure and the DSC module was fine, but by wiggling the DSC module connector I could tell that the internal connection within the DSC module between the pressure sensor ground (pin 25) and the external ground connection (pin 5) was the problem.

290 without my foot on the brake

$99 for an ABS module refurb is not a bad deal, might as well get that done just for the sake of it.

i am afraid that will not fix my problem,

i am gonna take the car to a BMW specialist, hopefully he will diagnose it and if he starts changing parts that dont do anything, it will be out his pocket.

[IcemanBHE]

if he starts changing parts that dont do anything, it will be out his pocket.

You think....

[seven11]

You think....

well... i am not gonna pay for his mistakes

[mgalvin1]

With my DSC ECU I only had one light that came up ( the one in the middle with a triangle in a cyrcle ) the BMW bloke has taken mine out now so I can send it off somewhere and he put another faulty one in , he told me that this one was in a worse condition than mine and wasn't repairable . With this one in my car I have three lights up ! The abs light , brake light and that triangle one in the circle , sometimes I'm driving along and they will go off and two miles up the road they come back on again , he said he's seen worse one were the speedo even stops working ! Another block I know had the same problem with all three lights up on the cluster and when he sent his off to be repaired they sent it back and told him it was unrepairable and charged him £50.00 ! . I don't know anyone who had had there dsc repaired and I am weary to how long would it last ? .

[mr7402u]

I FINALLY fixed this issue with my 2000 740i M Sport. The problem showed up directly after changing the Master Cylinder. Both DSC and ABS lights on at about 20 mph.

What was done:
* Put in a second new master cylinder. No change
* Swapped out the pre-charge pump. No change
* Rebuilt the ABS module. No change
* Swapped the pressure sensor twice. No change
* Replace the ABS hydraulic block. BINGO!

We haven't investigated why the block was the problem. I can only imagine junk got in the block. There were no obvious signs it was bad but replacing it fixed the issue.

[Pdelpres]

My 2001 E38 had the trifecta problem as well. The symptoms were

1) The lights would come on after a couple minutes of driving
2) Scan tool showed a code of 92 (Pressure sensor)

The solution was a new DSC compressor (also known as the pre-charge pump). It is really easy to test. Just hook up a battery to the terminals in the pump connector and listen for the sound of a motor. No sound and you will know your unit is bad. The replacement was $35 and the unit takes less than an hour to replace. You may find the following helpful

http://www.meeknet.co.uk/e38/ABS/Index.htm

That said, I found the no-bleed installation process to be more difficult than a normal bleed with the pump energized

Good luck

[AHolland]

I have a short comment and question on this issue. I also have the ABS and traction control lights coming on all of the time and I have no speedometer at all. If I drive for a while sometimes the lights go out and the speedo comes back. The car had this problem when I first bought it and then it quickly went away and was gone for more than a year. Lately it has come back again though. I got an AMS control module for a person that was to fit a 98 740i. When I took it home and went to change it out, I found I had a completely different control module. The person who sold me the module and seems to know his stuff said it looks like I have a 97 control module. There seems to be a lot of changes to the 740 in mid year whether water pump, AMB module and more. All the changes seemed to be at a cutoff time of 09/98 and later and those cars before.

My question is with regards to the coding to the car. This same person said that earlier models did not need to be recoded and he was not sure but he thought that cars with my module (Pre 09/98 built date) did not need to be recoded to the car. Can anyone comment on this?