Hey everyone, hoping to get some insight on a frustrating issue. Every once in a while my ABS light goes on. If I wiggle the front brake lines a little on each side, the light goes off once I drive a few feet. This happens about once a month or so. My scanner never picks up a code, probably doesn't have the capabilities. Any ideas, I'm guessing wheel speed sensor.

 

If the light has come on several times, you will have a DTC stored in the computer. You need to find a code reader that can pull that DTC. Otherwise, everyone will be just guessing as to what the problem is or could be.

These are the possibilities:

 

You're right. You're scanner doesn't have the capabilities, because if the ABS light goes on, by definition a code will have been set at the time the light turns on.

If a certain number of drive cycles over 10 mph happen without the module detecting the same fault, the light will go out.

One thing you can do to test your ABS sensors is get a DVOM set to OHMS and measure the resistance between the two pins on the wheel side of the connector at the rear of each front fenderwell. You are looking for around 700 ohms, more or less.

Do not attempt to back probe the connector... just disconnect it. Since the pins you will be measuring are male pins, it is a bit of a trick to keep your meter probes in contact with both pins at the same time, so take your time and makes sure.

If you have a helper, then you can have your helper wiggle the harness while you are checking resistance. If the resistance value changes dramatically (goes to OL, to zero, or to above 1K) as your helper wiggles the harness, and you are sure you've maintained good contact with your probes on the pins, then you've found your smoking gun. Obviously, you will need to check both sides of the vehicle.

Before rushing to change that front ABS sensor and mini harness though... be aware that Ford fetches up to $175 for the front ABS sensors alone... about 8 times the cost of the rear ABS sensor that is mounted on the differential (for most Ford trucks, except those with electronic stability/traction control systems). Heck, for just $25 more, you can get an entire new Timken unit bearing, which INCLUDES a new ABS sensor and harness. So you might want to dovetail front wheel bearing, axle seal, rotor/pad/caliper, and even ball joint replacement with your front ABS sensor replacement.

 

I've had the rear ABS sensor go out a number of times. Good idea to inspect and clean (it's a magnet for the rear diff fluid to boot). You'll find it on top of your rear pumpkin. One bolt holds it in place.

Front sensor is easy to get to also, if you go in there be sure to run some lube in that hole to make your front unit bearings last much longer.

 

Life lessons learned on FTE

 

Unless you have a dual rear wheel. Then the front sensor is a bear to get to, as the cast front wheel adapter has to be removed in order to get the rotor off without removing the wheel bearing. 16 to 20 more nuts, and they can't be zip zip zipped off or on with the impact, as the extended anvil has to be guided through individual access holes without the socket on so it will fit through, then the socket can be mounted... and this must be repeated for each nut. PITA.