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Discussion Starter #1
I have a 95 GMC K2500 that has been giving me an intermittent ABS Light. I think its coming from the front left sensor. I'm not 100% sure and don't want to replace sensor unless needed. Does anyone know if this problem will store any codes in the computer, and if so, how do I get them, what do they mean and how do I clear them. I'm familiar with getting engine codes from the OBD-1 computer. Any help is appreciated.
 

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use the scanner to access the abs module, it should have codes stored. go from there.
 

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Discussion Starter #3
Thanks for the reply. I forgot to say that my high tech scan tool is a paper clip connecting the A and B terminals in the data link connector. Is there a similar technique to access abs codes?
 

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Commissioner Gordon
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As long as it is obdI (95 went both ways) you can access the ABS by jumpering either A-H or A-G. I think it is A-H, A-G is air bag.
 

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Discussion Starter #5
Thanks for the info. Rttoys. The computer is OBD-1. Is there any place I can look up the ABS codes?
 

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Commissioner Gordon
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Post the code I'll look it up.
 

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Discussion Starter #7

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Commissioner Gordon
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12- normal system, this means nothing

25- left front wheel speed sensor or circuit open
26- missing left front wheel speed sensor
27- erratic left front wheel speed sensor

66- open or shorted pump motor relay

Just a guess, but your L/F WSS is probably toast; use an ohm meter and check for an open to be sure. From the left wheel, follow the speed sensor from behind the wheel to the frame connection. Ohm wires towards the sensor, probably 'OL', if not ohm towards the ABS module.

After you fix the L/F WSS problem clear codes (disconnect battery or cycle ignition a few times) and do a couple of ABS stops. This will make the motor and module move and work and usually fixes the code 66. That is better than the $x00 alternitive.
 

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Discussion Starter #9
12- normal system, this means nothing

25- left front wheel speed sensor or circuit open
26- missing left front wheel speed sensor
27- erratic left front wheel speed sensor

66- open or shorted pump motor relay

Just a guess, but your L/F WSS is probably toast; use an ohm meter and check for an open to be sure. From the left wheel, follow the speed sensor from behind the wheel to the frame connection. Ohm wires towards the sensor, probably 'OL', if not ohm towards the ABS module.

After you fix the L/F WSS problem clear codes (disconnect battery or cycle ignition a few times) and do a couple of ABS stops. This will make the motor and module move and work and usually fixes the code 66. That is better than the $x00 alternitive.
Thanks Rttoys for the info and pointing me in the right direction. I'll be pulling the sensor out after I solve a starting issue.
 
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