looking for a 3200 ABS faulty module

Contigo said:

I checked my ABS sensors and all seemed fine and no codes present on the SD2.

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How did you manage to check the sensors via SD2 if the ABS ECU is not communicating?

Physically checked them inspection. You can also measure resistance apparently but I don't buy that a faulty sensir can blow the ECU.

Contigo said:

Physically checked them inspection. You can also measure resistance apparently but I don't buy that a faulty sensir can blow the ECU.

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I was of the same school of thought as this , I too measured resitance with MM and confirmed all were in tolerance .

I think it's a bit more complicated than that.
You should rotate the wheel and measure with a frequency meter or oscilloscope the hall voltage output to make sure it's pulsing when the wheel spins.

But anyway, a faulty hall sensor should not damage a well designed controller.

jluis said:

I think it's a bit more complicated than that.
You should rotate the wheel and measure with a frequency meter or oscilloscope the hall voltage output to make sure it's pulsing when the wheel spins.

But anyway, a faulty hall sensor should not damage a well designed controller.

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It was and I did ! , I did not bother going into full detail , just stating that I took steps to eliminate other things before I was sure it was the module.

jluis said:

I think it's a bit more complicated than that.
You should rotate the wheel and measure with a frequency meter or oscilloscope the hall voltage output to make sure it's pulsing when the wheel spins.

But anyway, a faulty hall sensor should not damage a well designed controller.

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You are right it shouldn't. And that is not what I said happent. What actually happen is the abs light started coming on intermittently. I got the unit plugged I. The sd3 and the error was on the rear n/s sencors. This went on for about a month after which the abs light came on and stayed on. The error after that was no comms with the abs ECU. I replaced the ECU and plugged in an oscilloscope to the sensor input of the ECU and there seemed to be a problem with one of the teeth. Took a wheel off and one if the teeth was badly corroded. I then filed it and shaped it and all was good for a while. Then the whole thing started again with the abs light with a final no comms error. I then replaced the ECU and the phonic wheel. This was a bout 2 years ago and I have not had any abs problems since.

When I had all the issues the other thing that as happening, at speed, it felt like the power was ever so slightly coming on and off. It all went away though with the final repair

So, what do you think was the mode of failure?

Bill I have the same symptoms of coming on and off power but my ECU is dead. How does one explain that as the sensor or ECU can't be doing any feedback with a duff module.

I don't know about your car or your ECU. I am only describing what happen with mine. These ECUs have different modules within them. It is possible the ECU is still working but it's not communicating. The abs system is a sub autonomous system which communicates with the rest of the car systems through a CAN network. If the can controller can not communicate with the abs ECU it turns the bulb on the dash. Try hard braking on gravel. Does the abs work? Where it's safe to do so of course!!

I was going to suggest the same as Bill to check if your ABS still works.
Bill, about the on/off power, could it be the traction control engaging that gave you that feeling of power loss?

If one phonic wheel is faulty it will tell the ABS ECU that one of the front wheels spins faster than the other, triggering a reaction from the ABS system.

Yes, that is what the facts are suggesting. What would be useful if indeed there is a comms module, I imagine it would be standard across the bosch range. if one was to replace this with a known working one to see if they stop sulking and start communicating again!

Just spoken to a place that has repaired more mundane units for a good friends garage . They said they could repair the unit but would not be able to perform a final extensive test on the unit due to the software being different to the more regular units and not compatible with their tester . However the guy I spoke to said it should be pretty apparent with the experience they have what is the matter with it and if they can perform a repair or not . If this could help anyone let me know and I will provide details.

cheers

Be aware that these ABS units have custom microchip dies on them and not a single one of them is a replaceable item.
This is why the cover of the ABS controller is sealed and it must be destroyed to open the unit.
It was designed as a cheap non serviceable item.
The problem is that auto makers put a huge markup on something that is quite cheap to build.

All that the "repair" companies are able to do is rewire the board to the connectors whenever the fault is caused by a broken wire (Most common failure).

You can see that in this picture of a board:
http://www.bimmerfest.com/forums/attachment.php?attachmentid=228226&stc=1&d=1272646721

Those big squares in the middle are microchip dies that have not been packaged and are covered in silicone to protect them.

The quality of this repair varies from shop to shop.

Some shops use the correct soldering method and remove the silicone goo before doing so.
In the end they apply a new coating and a new cover.

Some other "shops" simply make a big mess with a standard soldering iron and render the board useless or prone to failure a few km's later when the unit is subject to vibration.

I would not trust my life to an ABS unit repaired this way as a malfunctioning solenoid would mean a "No brakes" condition.
Something you should avoid in any car, especially a 400HP beast while doing spirited driving.
I know that the units are engineered to fail in a way to prevent this situation but I would still avoid it.

Either way, if it's not broken wires, it's not fixable.

jluis said:

Be aware that these ABS units have custom microchip dies on them and not a single one of them is a replaceable item.
This is why the cover of the ABS controller is sealed and it must be destroyed to open the unit.
It was designed as a cheap non serviceable item.
The problem is that auto makers put a huge markup on something that is quite cheap to build.

All that the "repair" companies are able to do is rewire the board to the connectors whenever the fault is caused by a broken wire (Most common failure).

You can see that in this picture of a board:
http://www.bimmerfest.com/forums/attachment.php?attachmentid=228226&stc=1&d=1272646721

Those big squares in the middle are microchip dies that have not been packaged and are covered in silicone to protect them.

The quality of this repair varies from shop to shop.

Some shops use the correct soldering method and remove the silicone goo before doing so.
In the end they apply a new coating and a new cover.

Some other "shops" simply make a big mess with a standard soldering iron and render the board useless or prone to failure a few km's later when the unit is subject to vibration.

I would not trust my life to an ABS unit repaired this way as a malfunctioning solenoid would mean a "No brakes" condition.
Something you should avoid in any car, especially a 400HP beast while doing spirited driving.
I know that the units are engineered to fail in a way to prevent this situation but I would still avoid it.

Either way, if it's not broken wires, it's not fixable.

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Thanks for info - by the sound of it you have had some bad experiences .....

Anyway I have had loads of electronic units repaired over the years , this is a large UK company that does many electronic component repairs and my friend's garage uses them regularly - if you want their details I will be happy to pass them on . I thought it may benefit someone to get a repair done for a very sensible price and maybe people that have old units sitting around may want see if they could be repaired. I am sure that people are more than aware of the potential issues here and after 30 years in the motor trade I would not offer to pass on the number of a company that had not already proved themselves . I am not advocating that people should go get their abs module repaired - I am merely offering them the chance to speak to someone who may be able to help if they wish them to.

Obviously a repaired unit can fail , but so can an original bosch unit as has happened to many people on here , this I am sure for most of us did not lead to a "No Brakes" condition but a "No Abs" condition (which I drove with for quite some time) which I and many owners are probably used to as this is how they learnt to drive , come to that - with no pas , or traction control as well ...... remember cadance braking LOL

Anyway I have had abs modules repaired with good results and kept the car for many years . Anyhoo if it helps anyone to sort a problem out .

I would like details as soon as I get round to getting the module off the car.

Contigo said:

I would like details as soon as I get round to getting the module off the car.

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Sure thing Phil , will pm it over . If you are just taking the module off and leaving the pump etc in situ it is a very quick job , I think from memory you may have to loosen the bolts on the pump to wiggle it round a tad . But car can still be moved and driven with this off .

No bad experiences yet because I had no unit failing yet
I just took interest in this topic when I saw that both my 3200 and my old volvo have the same abs unit (hardware wise)

A properly repaired unit should last a long time as far as the wire replacements are concerned.

My only concern is the possibility of contamination of the dies.
Even if the probability of such event causing a breaking problem is very small, I would not want to take that risk in this car.

If they can be reprogrammed, they could possibly be used from other cars at more affordable prices.

As an alternative I'm exploring the possibility of getting new units from a dealer where I have a contact at a very reasonable price.

After removing the module, be sure to wrap the solenoid area to prevent them from bouncing around and bending the metal contacts.

Fitted a replacement module this evening but still got ABS / NO ASR lights on dash. Mind you haven't driven the car as it got a flat as I pulled into the garage!

Annoyingly because of the flat and being distracted I left the ignition on first click and when plugged the new ECU in saw an arc/flash!

I just hope that I need to drive the car tomorrow over a certain speed to reset the parameters!

You will probably just need SD3 to clear the error Phil.

There might have been an error but the warning goes off if it's not current when u drive above 10kph