ABS SENSORS FIXED!! FINALLY..
03-08-2005, 04:00 PM
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ABS SENSORS FIXED!! FINALLY..
I finally spent some quality time analyzing my ABS sensor problem and I came up with a fix.
Being a DIY with less than the necessary understanding, I tend to screw up a lot, like when doing the suspension, I didn't know the connection for the ABS/ Brake cable was just behind the grommet in the front wheel well. Damn me.
So I broke a rule.
I used vibration/heat/moisture proof connectors and repaired the jerky mistake. The ABS worked fine for a while.
But every sunny day has DS on the lawn.
My Brakes get done one day, and suddenly, the ABS 3 days later goes out.
I rode around with the agonizing alarms, until I could inspect the wheel well, and what do I discover? The mech didn't restrap the ABS line to the various posts, and the tire had worn out the cable for the ABS sensor/brake sensor.
I pulled the thing, and considered buying all 4 sensor wires, but couldn't find a full set used.
Someone on this forum said all needed to be OHM resistance balanced, or the ABS would cry and cry and not work.
WELL ON THIS CAR< THAT ISN"T TRUE!!..Thank someone!!
I took both sensors off of the front of the vehicle, (not chopping them up in the process) and measured the wiring. I went through several boxes of misc cable I had, and hit upon a light diameter computer power cord. I examined it, tested it for resistance, and mated it with another one.
Long Story, not longer, I rebuilt the cables for the ABS, making sure that the front signals were matched side to side, and using improved butt-end connectors, checking ohm resistance levels at every junction I installed, (gotta use those AUDI connectors, since noone carries the small pins anymore)and gained only 30 ohm resistance values by swapping the cables.
The lessons learned:
THe length of the cable from side to side should match. The connector sets should match in number of sets per cable. The balance of the system is nonsense in this ABS system, because for instance, I have 3 cables with 1267-1278 ohms resistance value readings (on a consistent basis for at least the last 8 months)(200k ohm setting on the multimeter) and the passenger rear, the odd man out, is at 1520. The ABS system seems fine with this anomaly.
So. My problem when I rebuilt the cable the first time was stability of the connections under vibration, and making sure that they are protected against moisture,and more importantly, protected against current leakages (making sure the wire sheathing up to the connection point on the bundled wires I exposed from the sheathing were completely covered up to the point at which they are contacting the connection device *pin.. While this type of caution shouldn't be necessary for all electrical work, it should be relevant to all sensors in the car, such as cam sensor wires, temperature sensors, oxygen sensors, etc. Consistency and completeness are the techniques I learned. If you screw up a wire, just make sure and try to match the wire diameter, materials, and shielding if you have any. Make sure the connections are stable, and clean. Use the right size connectors, and be consistent in the connectors and lengths of wire on two pole (2 strand)cables, (cut both the same length between connectors). This helped me solve a minor (replacing 1 abs cable), but potentially an expensive ($800.00 for all four if they had to match ohm resistance readings as was pointed out in the last :"search" that I did on the subject)
Comments??
Being a DIY with less than the necessary understanding, I tend to screw up a lot, like when doing the suspension, I didn't know the connection for the ABS/ Brake cable was just behind the grommet in the front wheel well. Damn me.
So I broke a rule.
I used vibration/heat/moisture proof connectors and repaired the jerky mistake. The ABS worked fine for a while.
But every sunny day has DS on the lawn.
My Brakes get done one day, and suddenly, the ABS 3 days later goes out.
I rode around with the agonizing alarms, until I could inspect the wheel well, and what do I discover? The mech didn't restrap the ABS line to the various posts, and the tire had worn out the cable for the ABS sensor/brake sensor.
I pulled the thing, and considered buying all 4 sensor wires, but couldn't find a full set used.
Someone on this forum said all needed to be OHM resistance balanced, or the ABS would cry and cry and not work.
WELL ON THIS CAR< THAT ISN"T TRUE!!..Thank someone!!
I took both sensors off of the front of the vehicle, (not chopping them up in the process) and measured the wiring. I went through several boxes of misc cable I had, and hit upon a light diameter computer power cord. I examined it, tested it for resistance, and mated it with another one.
Long Story, not longer, I rebuilt the cables for the ABS, making sure that the front signals were matched side to side, and using improved butt-end connectors, checking ohm resistance levels at every junction I installed, (gotta use those AUDI connectors, since noone carries the small pins anymore)and gained only 30 ohm resistance values by swapping the cables.
The lessons learned:
THe length of the cable from side to side should match. The connector sets should match in number of sets per cable. The balance of the system is nonsense in this ABS system, because for instance, I have 3 cables with 1267-1278 ohms resistance value readings (on a consistent basis for at least the last 8 months)(200k ohm setting on the multimeter) and the passenger rear, the odd man out, is at 1520. The ABS system seems fine with this anomaly.
So. My problem when I rebuilt the cable the first time was stability of the connections under vibration, and making sure that they are protected against moisture,and more importantly, protected against current leakages (making sure the wire sheathing up to the connection point on the bundled wires I exposed from the sheathing were completely covered up to the point at which they are contacting the connection device *pin.. While this type of caution shouldn't be necessary for all electrical work, it should be relevant to all sensors in the car, such as cam sensor wires, temperature sensors, oxygen sensors, etc. Consistency and completeness are the techniques I learned. If you screw up a wire, just make sure and try to match the wire diameter, materials, and shielding if you have any. Make sure the connections are stable, and clean. Use the right size connectors, and be consistent in the connectors and lengths of wire on two pole (2 strand)cables, (cut both the same length between connectors). This helped me solve a minor (replacing 1 abs cable), but potentially an expensive ($800.00 for all four if they had to match ohm resistance readings as was pointed out in the last :"search" that I did on the subject)
Comments??
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