ABS Control Module Malfunction

[X53Jay4.8is]

Have any of you with the X5 E53 have a defective ABS control module malfunction where the vehicle goes in into trans fail safe mode but none of the ABS instrument cluster lights come on? Only codes that are showing are below:

Code 20 EGS: Signal Speed n-output
Code 78 DME: Signal vehicle Speed

ABS/
Code 1F DSC: Wheel Speed Sensor rear right transmits no signal
Code 21 DSC: Wheel Speed Sensor front left transmits no signal

I find it highly unlikely that both wheel speed sensors would be out/non transmitting. Please share

I should mention that the check engine light comes on after the trans fail safe mode error comes on. There are no other dash warning lights. the vehicle has 62K on it 4.6is. Trans shifts fine and then locks out to one gear.

[g300d]

I'm helping a friend right now who has a similar problem on his 02 3.0 with 30k miles.

Car has not been used for a while. Put in a new fuel pump and it's running now, but has the trifecta and cog of death lights on. Shifts through the gears but a bit rough shifting.

Scan showed MAF, ABS module fault, and something about CAN torque, didnt see the actual readout.

We're putting in a new MAF first but I have a hunch it might be ABS system related as a few posts in some e39 forums mention it too.

They suggest pulling the ABS module plug and driving around to check, it works for some. It didnt work for us though.

[X53Jay4.8is]

Okay I went through the analysis with my Brother who is a master Mechanic and we deduced that the ABS/DSC control module is faulty. We used the scanner to check the readings at the wheel. I had two codes saying that the wheel speed sensors at the left front and right rear are defective. So we hooked up the scanner, went into live data and we could see that 3 of the 4 sensor channels were reading but the right rear one had no communication. We swapped the rear sensors from side to side and no reading was detected to the right rear wheel. So the sensors are good but a fault lies between the DSC module and wire that feeds to the sensor. Anyway we change the ABS/DSC module and VIN coded it to the vehicle. We left the scanner connected in live data and immediately upon driving signal communication was achieved from all four wheel sensors. So ABS /DSC unit defective. Keep in mind the while the ABS/DSC unit was defective none of the usual suspects of lights came on as had been discussed in some of the Xoutpost discussions (for instance triangle warning, ABS light, etc.). The vehicle would just go into trans fail safe mode and then the SES light.

[g300d]

Gotcha! Good you were able to confirm it was the module.

Did fixing that resolve your trans problem?

If it did, would you know how the ABS system affected your trans? Guessing the trans needs the signals that the module was not outputting?

[X53Jay4.8is]

Originally Posted by g300d

Gotcha! Good you were able to confirm it was the module.

Did fixing that resolve your trans problem?

If it did, would you know how the ABS system affected your trans? Guessing the trans needs the signals that the module was not outputting?

Yes the Trans problems were completely eliminated when the ABS module was replaced. Since there was no speed signal reaching the trans it caused the trans to enter trans fail safe mode. My trans operation is back to normal with smooth and crisp shifting. Like I said before it was odd that the defective ABS module did not exhibit any of the usual trifecta lights that so many BMW enthusiasts post about. Everything about this ABS unit functioned with the exception of the reading to the rear right wheel speed sensor. As a matter of fact the previous owner tried to fix the situation by installing a new wheel speed sensor but they obviously miss diagnosed the real problem of the car.

[g300d]

I see. Good info, thanks Jay!

[tomsawyer]

Jay, I'm curious - how much did you pay for the module? Thanks

[X53Jay4.8is]

Originally Posted by tomsawyer

Jay, I'm curious - how much did you pay for the module? Thanks

As I understand there are two modules that are possible for the vehicle. I was lucky that my vehicle was outfitted with the less expensive one. I paid $431 for the new Bosch unit. Other Module is a more expensive one and can only be acquired from the dealer if you want a new one. It costs roughly $1300. I would imagine this is why so many people will try to get the ABS unit rebuilt as opposed to buying a new one.