ABS light on? Wheel speed sensors clean? Have you looked at your wheel speed sensor wires?

I finally just replaced the wheel speed sensor wires for both my front wheels - at 72K miles, the wires to the wheel speed sensors on both sides had gone, and I had the ABS/DSC/Trac warning light and message on permanently.

It is possible to replace the whole wire assembly from the wheel speed sensor to the connector in the engine bay, however, a new wire is over $100 and used ones on ebay are still in the $30-$40 range.

My car is a 2006 XKR, you may wish to double-check that the connectors I recommend are the same ones for your car.

You will need:
- A replacement connector (more on that in a moment)
- crimp-on butt splices (preferably the ones that are heat-shrink and adhesive lined). I used blue 14-16ga crimps.
- Half a roll of Self-amalgamating tape per wheel (ask for it specifically - not electrical tape). I used "Versachem WrapIt Repair" self-fusing silicone tape from AutoZone.
- A wire tie
- Normal shop tools (jack and stands, safety glasses, wheel wrench, 8mm wrench, side cutters, crimp tool, wire strippers, continuity meter or multimeter, razor knife, a heat gun or lighter, and a cold beverage)

Replacement connectors: I searched high and low for these things. As far as I can tell, the only OEM ones available are already attached to the $100 wires I mentioned in the beginning. I used two different kinds: a connector part number PT187 sold as an oil level sensor connector, $27.99 and in-stock locally at Advance auto parts, and a HP4720, $8.59 plus shipping from Rockauto.com . They appear identical.

There is also an S575 ($17.31 from Rockauto) which has very similar pictures to the other two online, although I didn't order one, so I don't know for sure.

So if I were doing this again, I would order two (or four) HP4720's from rockauto.com.

Procedure:

Car jacked up and supported safely, safety glasses on, wheel removed, etc.

Disconnect the wheel speed sensor wire and inspect.

First determine if the wires have broken connections or not, especially right where the wire meets the connector. Look really carefully. (first photo). Mine broke as I was inspecting them. You may wish to use the continuity meter between the connector in the engine bay and the connector at the wheel speed sensor, and wiggle the wire around to see if the connection is intermittent. If they haven't gone yet, tape them up with some self-amalgamating tape and leave them alone (a ten cent strain relief boot added when these were manufactured would have stopped this problem entirely).

There are two wire ties holding the wire to a support strut. Cut the one closest to the wheel, and then cut the wire just past the thick rubber grommet. See second photo.

Prepare the replacement connector. Remove the blue cover thingy (not sure what that's for) and put on some safety glasses before using some side cutters to clip off the plastic shoulders that held the blue cover thingy on. Mine flew off with quite some force - wear eye protection. See third photo (the left shoulder is cut off, the right one is still in place so you know what I'm talking about, but you're going to remove both shoulders)

I'm going to assume that polarity matters. The replacement connector has 2 black wires, figure out which one was the brown wire on the original connector and mark the same wire on the replacement connector the "brown wire" to match whichever one was the brown wire on the original connector.

Use the self-amalgamating tape to make a waterproof, stress-relief boot. If you've never used self-amalgamating tape before, it's not sticky, it sticks to itself when you stretch it. So you need to stretch and pull to make it stick. Don't skimp on the tape. See fourth photo.

Continuing using the self-amalgamating tape, gimp up the wire until it's about as long as the original wire that you cut, and then for good measure keep wrapping it back down and create a second layer and more strain relief. See 5th photo.

Very carefully and slowly, use a razor knife to cut through the outer insulation on the original wire, about 2 inches from the end of the wire, being very careful not to nick the insulation on the interior wires. The outer insulation is very tough, so go slow and only cut a little at a time. It may help to bend the wire into an arc to make the wire split a little as you cut it. Strip about 1" of insulation from each of the interior wires, fold it back on itself, and twist to keep the strands together. Insert the twisted end into a butt splice and crimp.

Lay out the replacement connector for length. Mine were supplied with about an inch more wire than I needed. The final length we're looking for here is so that the butt splice can lay flat on the support arm in between the two protrusions that the wire ties will go around. You also don't want the wire to the wheel speed sensor to be so long that it interferes with the brake disc. Too short is also a problem because it will strain the wire. There is a theory that the wires were all too short to begin with and this over-strained them, so my finished wires were about 1/2" longer than the original wires.

When you are satisfied with the length of the replacement connector, trim the wires to length and strip the ends. Connect the "brown" to brown, black to black (use a multimeter if you forgot which one is the "brown") and crimp. See 6th photo.

Connect the new connector into the wheel speed sensor. Now is an excellent time to go and turn the ignition key to see if the ABS warning has gone out in the dashboard display. If it hasn't gone out, you either have more than one wheel with a break, or you did it wrong, or you have another issue, so re-check your work.

If you're using heat-shrinkable, adhesive-lined butt splices like I have, heat them up until they shrink and the adhesive oozes out a little. This will provide extra mechanical strength and waterproofness for the join. See 7th photo.

Now use more self-amalgamating tape to gimp up the whole thing right up to the original wire. Make an extra-big thickness where we're going to join the wire back to the support arm. See 8th Photo.

Join the wire back to the support arm with a new wire tie. See 9th photo.

Reattach wheel, lower car, torque wheel nuts appropriately. Done!

Enjoy the following benefits:
- Avoid having to look at that annoying yellow light and message
- Avoid dying a horrible death in a tragic collision and ensuing fireball that would have been preventable if only your ABS and DSC had been working.