From digest.v7.n1019 Mon Jan 26 10:22:31 1998
From: "Alan Alfano"<Alan.Alfano_at_SNET.com>
Date: Mon, 26 Jan 1998 07:34:26 -0400
Subject: Re: E30 ABS analysis [long]
In v07.n1001, From: Paul Cuaresma <cuaresm_at_hawaii.edu>
>I am having problems with my ABS system on my 325i. The ABS malfunctions
>everytime I turn the car on now.
In v07.n1006, From: Christopher Pawlowicz <chrisp_at_doe.carleton.ca>
reposted previous posting from: Kenn(y)(eth) Sebesta, in summary Ken
>1) Check the ABS wheel sensors.
>2) Check the ABS relays
>3) Check the instrument cluster ABS lightbulb for the system.
>4) Check the ABS pump.
Sorry to be running a little late with my response..
In addition to Ken's checklist, you may want to consider trying the
following ABS checks:
- Incorrect Jump Starting
If one incorrectly reverses the connections (even momentarily), a relay
attached near the top
ABS control unit which is located under the dash, left of the steering
wheel will get toasted.
Discount parts vendors sell this for approximately $21.
- Intermittent ABS Warning Light
The ABS warning light may come on intermittently, and normal
do not indicate any defect. This can happen when the vehicle is driven over
50 mph, or on
cars that have recently had two new tires, or snow tires installed.Check
all four tires on the
car to make sure they are all the same brand, style, and size. Also note if
there are any
new tires with substantially more tread than the other tires. Differences
in tires may cause
enough variance in rolling diameters to confuse the ABS control unit, which
may give a
false signal to the ABS warning light. This is especially true if snow
tires have been
mounted on the rear wheels only.
- ABS Wheel sensors
Some 3 Series vehicles may experience a situation in which, during braking,
will activate even though the brake application is light and traction is
good. This may
be caused by the pulse ring being loose on either front wheel hub, which
pulse ring to rotate, sending a false input to the ABS control unit. If
this condition is
found, replace the front wheel hub with the loose ring.
- ABS Sensor Lead Faults
If a problem was encountered in an ABS Sensor Lead, the repair is
the vehicle main harness. Separate leads are now available that allow
replacement of each of the 4 separate sensor leads. In most cases a fault
in a sensor
lead will show up as an intermittent fault (ABS warning lamp comes on
These sensor leads are available under the following part numbers.
(One lead and the necessary connectors for the repair are included in each
Sensor lead E32/E34 - P/N 61 13 9 061 686
Sensor lead E30 - P/N 61 13 9 061 687
I hope this is of some help,
BMW CCA #30492
1988 BMW 325iX
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1956 Austin-Healey 100M (2)