Sunday, April 1, 2012

"1998 BMW 528i SE: How To Change The ABS Module"

Silver 1998 BMW 528i SE Front Left

How can I change the abs module on my 1998 BMW 528i SE? The gear box is in safe mode and abs light is on. I’m told its the abs module, does anybody know where it is and how to change it?

Answer: I would advice taking the vehicle to an experienced mechanic. It does not sound like you are very experienced in auto repairs and ABS systems can be difficult to fix correctly (purging the brake lines of air, etc). Is always easy to take it apart, but getting it back together (mainly working properly) is where the frustration really starts.
Hope you do follow my advice, and in good faith here is some more info.
Vehicle: 1998 BMW 5-series
ABS Module: Bosch 5.0 or 5.7
The ABS module is located on the passenger side (right side, as in US sold models, not sure if UK sold models are in same place) of the engine compartment, mounted on the strut-mount housing facing the engine.
You need a T20 Torx driver to remove the screws that hold it to the ABS modulator.
Removal
1) Carefully remove the connector by pulling out the locking tab.
2) Remove the 4 or 6 torx screws that attach the module to the ABS modulator.
3) Remove the module.
4) Cover the exposed surface of the ABS modulator, aluminum foil works good.
Your vehicle uses one of two ABS controllers.
• The Bosch 5.0 (4 screws) uses a solenoid module which mounts to the hydraulic unit. The pump is hardwired to the module without a connector. The actual controller is located under the dash or beneath the rear seat. (Has wires coming out of it)
This unit is not repairable, has to be purchased new.
Specialized shops are unable to repair the Bosch 5.0 module. Here’s why…
The module mounts directly to the ABS hydraulic unit. It contains only the solenoids which operate the hydraulic valves. The control electronics are located in the EBCM (Electronic Brake Control Module). This module is located under the dash or rear seat, away from engine heat, vibration, and weather. For this reason, these modules tend not to fail. However, when they do, the problem is usually due to a failed microprocessor. Since these chips are custom made, they are unable to find replacements for them.
• The Bosch 5.7 (6 screws) module, in comparison, is completely self-contained with solenoids and controller. (Will not have any wires coming out of it)
This unit is repairable by some specialized shops.

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