How would I know the ABS is working correctly on my BMW 2001(e39)

The instrument cluster receives the vehicle speed sensor (VSS) signal which originates in the ABS module and is transmitted to the PCM over the communication network. The PCM monitors the VSS input and sends it to the instrument cluster over the communication network. With the VSS input, the instrument cluster provides the speedometer with a corresponding pointer movement.

• The speedometer/odometer is inoperative

• Powertrain control module (PCM)
• Instrument cluster

• Go To Pinpoint Test F .

Pinpoint Test F: The Speedometer/Odometer Is Inoperative
Normal Operation Vehicle speed information is sent to the powertrain control module (PCM) from the anti-lock brake system (ABS) module. The instrument cluster receives the vehicle speed data from the PCM over the communication network.

Possible Causes
• PCM
• instrument cluster

PINPOINT TEST F: THE SPEEDOMETER/ODOMETER IS INOPERATIVE Your best bet ,have the vehicle hooked to a professional scan tool an checked for DTC'S - diagnostic trouble code's , before you replace parts that are not needed.
Test Step Result / Action to Take F1 RETRIEVE THE RECORDED DIAGNOSTIC TROUBLE CODES (DTCs) FROM BOTH THE CONTINUOUS AND ON-DEMAND PCM SELF-TESTS

• Check for the recorded PCM DTCs from the continuous and on-demand self-tests.
• Are any PCM DTCs recorded?

Yes
REFER to the Powertrain Control/Emissions Diagnosis (PC/ED) manual to continue diagnosis of the DTCs.

No
For an inoperative speedometer, GO to F2 .

For an inoperative odometer, GO to F3 . F2 CARRY OUT THE INSTRUMENT CLUSTER SPEEDOMETER GAUGE ACTIVE COMMAND USING THE DIAGNOSTIC TOOL

• Key in ON position.
• Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster Active Command.
• Select the instrument cluster speedometer gauge active command. Trigger the active command on. Observe the speedometer gauge. The speedometer gauge should start 16 km/h (10 mph) and move to 194 km/h (120 mph).
• Is the speedometer gauge within specifications?

Yes
GO to F4 .

No
GO to F5 . F3 MONITOR THE INTEGRATED CIRCUIT DISPLAYS

• Key in ON position.
• Monitor the compass, air temperature and message center functions of the integrated circuit display.
• Do the compass, air temperature, or message center displays operate correctly?

Yes
GO to F5 .

No
Go To Pinpoint Test U to continue diagnosis of the integrated circuit display. F4 CHECK FOR CORRECT PCM OPERATION

• Disconnect all the PCM connectors.
• Check for:
  • corrosion
  • pushed-out pins
• Connect all the PCM connectors and make sure they seat correctly.
• Operate the system and verify the concern is still present.
• Is the concern still present?

Yes
INSTALL a new PCM. REFER to Section 303-14 . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. F5 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION

• Disconnect all the instrument cluster connectors.
• Check for:
  • corrosion
  • pushed-out pins
• Connect all the instrument cluster connectors and make sure they seat correctly.
• Operate the system and verify the concern is still present.
• Is the concern still present?

Yes
INSTALL a new instrument cluster. REFER to Instrument Cluster in this section. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

Get a diagnostic code reader. Read more about them here:
http://www.bimmerforums.com/forum/showthread.php?1790673-cheap-code-reader-bmw-e39

Look up codes here:
http://www.obd-codes.com/trouble_codes/bmw/

sound like faulty vechicle speed sensor. what year model type vechicle working on.

You won't know the answer until you do something,
like check for codes & diagnose any codes related
issues & correct them first

Too many components in that system to guess at
a couple of common things,as you need to get to
work on having it checked out by an experienced technician

Pull the instrument cluster. These are prone to resistors burning out on the back of the cluster. It happened to mine. You'll need a soldering iron. I believe there are a couple of YouTube videos out there for this particular problem.

One thing that comes to mind is the use of plastics in dash components. Numerous vehicles suffer from same symptoms due to expansion and contraction in different temperature ranges which have been know to cause connection problems at connector in back of dash clusters etc. One dash I did required pulling cluster out, twisting connector pins on back of cluster slightly and re-installing for better connection, and problem cured. Might be a consideration.

ABS/ASC module is faulty
CLASSIC ABS FAILURE SYMPTOMS:
- Most of the time, the problem is the ABS module or one of the 4 wheel speed sensors (& sometimes the brake pressure sensor)
- In my 2002 BMW E39 DSC, three orange (warning) cluster display lights lit, ABS, Brake, & DSC
- The 3 warning lights reset when the ignition is turned off, only to repeatedly reappear within minutes of normal driving
- The fault is often intermittent leading you to falsely believe you've resolved the problem (proper diagnosis is important)
- Sometimes the fault only appears when the engine is hot; other times only at speeds over 40 mph
- Carsoft may erroneously show a rear speed sensor failure; but just replacing the speed sensor may make no difference.
- All the work is in correct diagnosis of the problem; parts replacement is trivial (from 1 to six bolts in a few minutes)
- Hence, this BMW E39 ABS 3-warning light DIY will concentrate on understanding and diagnosis of the problem

I would replace the Vehicle Speed Sensor (VSS) at the transmission 1st, also who advised the PCM (computer) was bad? a Jag dealer? I think they are guessing on that, computers rarely fail, maybe 2% of the time if that.

they have common problem with gears breaking in instrument cluster

It's not the fuse. You need to jump start the diagnostic cable. First you need a battery of 9v and short the + and - terminal to the diagnostic cable. Then you will see smoke. After that it should work fine.