So . . . the 3 Amigos have been on in my '01 Disco for some time. I replaced the shuttle valve switches in the modulator to no avail, so I've been looking for (and finally found) a new ABS modulator at a very reasonable price. I plan on installing it soon. Recently, however, the "Brake" light has come on as well. I pulled the codes and, in addition, to the shuttle valve switch failure i was expecting to see, there were several more:

"Sensor Left-Hand Rear (Sensor Air Gap too Large)
Sensor Left-Hand Rear (Intermittent Sensor Output During Driving, Broken Wire)
Sensor Left-Hand Rear (Sensor DC Failure, Broken Wire, Sensor Impedance too High/Low)"

I replaced the left-rear ABS sensor and cleared the codes, but within minutes of driving all the lights came back on. When I pulled the codes this time, I again had the "Sensor Left-Hand Rear (Sensor DC Failure, Broken Wire, Sensor Impedance too High/Low," and I'm guessing if I pulled the codes now all of the same codes would be there. I've looked for, but not found, any broken wires.

Should I look at replacing the wheel hub assembly? Is there a particular spot (maybe not easy to see) where the wire usually fails? Any help would be very appreciated.

Thanks.

 

I'm still a noob but in process to resolving the exact same scenario.

I've broken mine down to a couple issues/fixes:
- SVS- I'm just going to do the bypass for this. I think it's referred to as "option b" (actually going to let a shop do it as its friggin cold right now)
- BRAKE light- I think the switch is wonky in mine as I don't get any clicks when pulling the e brake up and the button sticks, but I've read about this having to do with brake fluid level as well.
- ABS sensor- how did you replace? I'm pretty sure I've read the current correct procedure is to wire- all the way to the Bay- and solder in under the dash a new one. Supposedly mine came with new sensors, but I don't think they are the "correct" ones for the fix. So I'm going to to do option b first and if that doesn't work, I'll start the process of doing the correct fix.

I'm no expert, but his is what I've read and been told by Great Basin Rovers

 

Thanks. I should have mentioned that, other than the ABS being disabled due to the variety of faults, the brakes (including the e-brake) are functioning correctly, and the brake fluid level is where it should be. It also hasn't been that long since I bled the brakes.

You're right about the ABS sensor and the current/preferred fix being to run it all the way to the front. On my '01 the sensor had a plug/disconnect near the wheel. I used the same type of sensor to replace it. Maybe I should try the new type sensor that has to be wired-in at the front...

 

I know this is a couple year old thread but it matched all of the relevant key words. Just went through fixing my 3 amigos + brake faults. Option B took care of all of the lights except ABS. Note that on my 04 DII, the lights did not go off immediately. Even after clearing the codes, they did not go off until the next morning (cold start required??). I still had the "Right front sensor erratic" fault, which was the cause of the ABS light.

In an effort to get it done quickly, I called the local stealership to see if they had a sensor in stock. They did not and added that it was likely a bad hub, and that they had never had any luck replacing just the sensor, and always just replaced the hub (which comes with a new sensor) -- several hundred dollars!! My hub seemed to be very tight so I did not take their advice. I did take the advice of Best4x4 and ordered a $15 sensor off ebay, as a first try at repair.

While waiting for delivery, I found a youtube video showing how to check for a good or bad sensor. Steady 950-1050 (milli-??)ohms resistance = good sensor. Unstable or decreasing readings (or obviously no reading) = bad sensor. The new sensor arrived, removed the wheel, inspected the old sensor and it all looked good. Was about to start on the rotor removal and remembered several comments here about cleaning the connections, etc., was all it took for some folks to remedy the fault. I disconnected the sensor in the engine compartment- all looked good, no visible corrosion- and checked the resistance - steady reading of 1000. Rotated the hub numerous times, no erratic readings. Sprayed the connectors with electronics cleaner, a dab of dielectric grease on the male prongs and put it back together. Put the wheel back on, cleared the fault code with the Foxwell, ABS light went off before I got out of the driveway and has been off now for 2 weeks. I suppose I'll keep the new sensor in inventory for likely future use.

Thanks to all the forum members for sharing their knowledge and experience. Saved me hundreds of dollars (possibly more!) on this issue alone. If I weren't a wrencher, and had taken it to the dealer for repair, no doubt they would have replaced the hub and who knows what else! As many of you have stated, this was a good lesson -- start with the simplest possible remedy first.

 

Well, they're back.
I've tried re-seating the connector in the engine compartment, cleared the codes, came right back on. Checked the wheel again, and there is no movement or "play" in the wheel bearing. Trying to decide what to do next. Long-wire sensor replacement? Could it be some other issue with the hub? Could it be an issue with the brake pads? (RSW mentions this on his website).