ABS help

[Gregory w Bender]

The abs light been on since we bought it. I new york state the abs doesn't need to work but i like it to work. I check the fuses and all good. I can't find the abs system relay. I know the computer for abs system by the radio under the dash. I know the back abs wheel sensor works since the cruise control works and uses the back wheel sensor. cording to carfax the brake system was flush and service back in the end of 2014 by the last owner. so my question is where the abs system relay? i figure i would check it and make sure its ok. thanks for the help.

 

[96eb96]

Why do you think it is the relay? The computer by the radio is the GEM, has little to do with ABS. The ABS computer is under the hood on the drivers side.

There are cheap scan tools that can read the code, maybe you need a front sensor. There is a software called forscan which is free and works with a cheap obd II adapter and can read the code and even monitor wheel speeds.

 

[J_C]

Assuming yours is the same, I don't see an ABS relay on the circuit diagram I'm looking at. It has just fuse 14 (10A) in the interior fuse panel, and fuses 7 (30A) and 3 (50A) in the under hood power distribution box. These go directly to the ABS control module.

I agree with 96eb96 that you may need to use a scanner or app like Forscan that can pull Ford specific ABS trouble codes. I don't know enough about the ABS module itself to tell you if there's anything servicable about it besides replacing the whole thing... $362 on RockAuto + $62 core charge. With a multimeter in frequency measurement mode you might be able to pick up the ABS sensor signal while driving, though I wonder if a scanner capable of ABS data could also pull this data.

Considering the age of the vehicle, not sure if a junkyard pull ABS module would work long term, if the fluid had drained from it then I wonder if the (o-rings?) seals inside would have hardened or disintegrated.

According to the following topic, Forscan can do that, however if the speed sensors aren't bad then all I know to do is replace the ABS module itself, unless it's just a wiring or bad connector issue. I don't know anything about the acceleration sensor, if it's prone to failure or what would happen with a bad or no reading from it.

FORScan forum • View topic - Recording wheel sensors

 

[Gregory w Bender]

I didn’t see the 50 amp fuse in my diagram I have. I have check that one. I know both front wheel sensors was replace two or three years ago. The back one is the one that came with it. I was told if the rear sensor goes bad the transmission and cruise control won’t work in it. The transmission won’t shift right and cruise control won’t work at all or not work right. It’s all most $200.00 to have a garage put a scanner on it. Thanks for the help I am getting.

 

[J_C]

Forscan plus a wifi or USB OBDII adapter for a Windows laptop, bluetooth or wifi android or wifi apple tablet or phone OBDII adapter, is around $30 or less if you can't get any place to read ABS codes for free. As far as I know the OBDII-only scanners at Autozone, Advance Auto, etc auto parts stores won't do ABS.

 

[96eb96]

I didn’t see the 50 amp fuse in my diagram I have. I have check that one. I know both front wheel sensors was replace two or three years ago. The back one is the one that came with it. I was told if the rear sensor goes bad the transmission and cruise control won’t work in it. The transmission won’t shift right and cruise control won’t work at all or not work right. It’s all most $200.00 to have a garage put a scanner on it. Thanks for the help I am getting.

I use the BAFX adapter, $20 and you are all set. There is value in forscan because it can read ANY code on your truck. It will scan every system in the truck and give you a report. Install on your PC, pair with BT and you are all set. It is possible the rear sensor could be a bit intermittent and the ABS picks it up. Without a code honestly it is a waste of time to think about it. Could be an internal failure in the module or a wiring issue. There could be damage to one of the tone rings in the bearings (and you can monitor wheel speed with forscan). Feeling lucky? Play lotto!