[Shotimes] Testing ABS

[Paul Nimz]

The ABS sensors are magnetic proximity sensors.  They sensors are meant to
differentiate the bumps and valleys of the ABS ring to send out a pulsed AC
signal.  You should be able to tap into the wire and when spinning the wheel
see the voltage come on and go off.  Don't know if it is 5v or 12V DC input.
The signal will be a pulsed DC output, which is a positive square wave AC
signal.

If you disconnect the sensor I would assume you would get a code.  You can
trigger the ABS to put out a pulsed signal via the dash warning light the same
way you can with the check engine light using a paper clip.  The ABS connector
is on the left hand strut tower.   But if there is a fault you should already
be getting a code via the warning light when you start the car and it does its
self test.  Does the ABS light come on when you start the car?

Here are the codes specific to the sensor.

DTC 31         Open or short circuit LH front sensor, wire harness

DTC 32         Open or short circuit RH front sensor, wire harness

DTC 33         Open or short circuit RH rear sensor, wire harness

DTC 34         Open or short circuit LH rear sensor, wire

DTC 35         Open or short circuit LH front sensor, wire harness, teeth on
front brake anti-lock sensor indicator, sensor air gap too small/large

DTC 36         Open or short circuit RH front sensor, wire harness, teeth on
front brake anti-lock sensor indicator, sensor air gap too small/large

DTC 37         Open or short circuit RH rear sensor, wire harness, teeth on
rear brake anti-lock sensor indicator, sensor air too small/large

DTC 38         Open or short circuit LH rear sensor, wire harness, teeth on
rear brake anti-lock sensor indicator, sensor air too small/large

DTC 41         Missing sensor signal LH front sensor (missing front brake
anti-lock sensor indicator

DTC 42         Missing sensor signal RH front sensor (missing front brake
anti-lock sensor indicator

DTC 43         Missing sensor signal RH rear sensor (missing rear brake
anti-lock sensor indicator

DTC 44         Missing sensor signal LH rear sensor (missing rear brake
anti-lock sensor indicator

DTC 55         Missing sensor signal LH front sensor (long term failure).

DTC 56         Missing sensor signal RH front sensor (long term failure).

DTC 57         Missing sensor signal RH rear sensor (long term failure).

DTC 58         Missing sensor signal LH rear sensor (long term failure).



The data link connector has 6 slots for wire connectors, holding it with 4 on
the bottom the second one in from the right is circuit 210 trigger circuit,
the one above it is circuit 503A ground, and the third in from the right on
the bottom is circuit 606 warning lamp.






I do not know which ones need shorted to make the lamp flash, probably 201 and
606.

Paul









On 7/22/2005 1:07:49 PM, Peter Chase (pbchase@gmail.com) wrote:
> Is there a way to test individual ABS sensors?  Whenever
> I'm coming to
> a stop, at around 5 mph, my ABS will come on, immediately dumping line
> pressure, making coming to a complete stop before hitting the car in
> front of me (or rolling downhill into an intersection) quite
> interesting.  I've
> now removed the ABS fuse to eliminate the problem,
> but
> I'd like to be able have ABS again someday.  Initially, I thought
> my problem was due to grease buildup on my lf wheel speed sensor due
> to a cracked CV boot.  However, since replacing the CV joint and
> cleaning all of the gunk off of the sensor, the problem remained.  It
> seems like as the car is coming to a stop and the wheels are barely
> turning, one of the sensors loses its signal and the car thinks it's
> skidding, activating the ABS.  Is there any kind of automatic test, or
> do I just have to unplug one sensor at a time and look for a
> particular type of signal as I manually turn the wheel?
> Thanks,
> Pete
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