Hi, all.

My first post, and it's just to help anyone out who had the same issues I just resolved...you know, so you can finally sleep better. This is a long post (sorry), but I think it is important to see the evolution of my process so you can pick a starting place for your situation. BTW - Where I live, you can't have any idiots lights on or you fail state inspection.

2002 Ford Expedition 4.6L 4WD

Problem: My ABS light was on, not intermittently, constantly. The only time it would stay off was when I would start the truck and kept my foot on the brake pedal. The second I released the brake, the ABS came back on.

I spent about 12 hours over several days researching this on various forums and videos. I bought a Bosch 1100 w/ABS ODB scanner from O'Reilly Auto for $89. Hooked it up and got a C1096 code, which is Hydraulic Pump Open Circuit. What could cause that? Well, apparently lots of things.

Some things that could cause this from my research (not EVERYTHING):

1. Bad speed sensors in wheels or on the rear. Not likely the issue, or I would have received a wheel sensor issue code (most likely). I replaced the rear sensor at $13 first just to cross that off the list. 5 minute job. I did learn that the harnesses for these rear speed sensors go bad occasionally as well and can cause issues/codes.

2. Weird one: Bad ignition coil can possibly generate an erroneous fault code disguised as an ABS issue. Again, not likely, and wasn't my issue. Not sure this is even "a thing", but it turned up in my research a few different times.

3. Blown fuse: There are several places where ABS-associated fuses are listed in the fuse charts. There is a 50amp MAXI fuse for ABS in the box under the hood., slot #102. Not blown. Also, there are some apparent discrepancies on some of the fuse charts vs. reality. I pulled every fuse in the truck and none were blown. I did learn about the 5amp fuse that will disable your windows and not let the truck out of park. #14 or #15 fuse. This actually happened to me the other day, oddly. Good idea to keep an extra 5amp fuse in the car in case so you don't get stuck at Wal-Mart at 11:00 at night on a Monday in the ghetto.

4. Bad Master Cylinder (MC): I saw some brake fluid around and in the cruise control brake safety sensor that is mounted on the MC. The plug & short fused harness had been replaced years ago with the new "safety" plug and harness, but it was in bad shape. Brake pedal had also been soft, so I suspected the MC may be bad. I bought a new MC ($43) and cruise control plug/harness ($20) on Amazon and got them in two days. Bench bled the MC, installed it, bled brake system, hooked up new Cruise Sensor and harness. Looks great. No leaks. Not the C1096 problem.

5. Bad ABS computer/module: Ok, this is where things got interesting. These things are big bucks new. In my Expy, there is a Kelsey-Hayes 325 ABS module. This sits under the air filter housing on top of the ABS pump motor and housing. This was a prime suspect for my issue from the loads of postings of people who had this same issue over the years. So, I wasn't about to buy a new one at the ~$900+/- price tag. These can also be sent out to be repaired for like $90. So, I took matters into my own hands....for better or worse. Removed my ABS module from the truck and after watching several painfully bad videos of people fixing theirs, I gave it a shot. Opened it by removing the rubber seal with a razor knife and prying it open with several screwdrivers. Inspected with a magnifying glass and then re-soldered all of the contacts inside. Sealed it up with silicone adhesive. I put it back on the truck and the same C1096 code existed. F word!!!! Maybe I screwed up the module (more). Ok, so I need to get a replacement. I call LKQ (junkyard that is networked in the US) and they have a used ABS "system" that gets shipped to my local LKQ in 3 days. $110 and it comes with EVERYTHING. Module, hydraulic pump, ABS housing, mounting bracket. Cool. Get it home, put on the new module and BAM!!!!, same issue, code C1096. Double F word!!! Problem is not the module, or I have now have two bad modules.

6. A bad wire: Several forums discuss faulty wires they found in the system for the ABS. They describe finding either a "swollen" (bulged) wire or a "soft spot" or loose section in the wire. When cutting the wire open, the notorious "green powder" is present and the corrosion has eaten most of the wire, making it not conduct properly. So, off I go combing wires. Several people mentioned finding a faulty wire under the fuse box that is under the hood of the car, near the Master Cyl. I did not remove the fuse box, but did my best to trace wires to and fro from the ABS system. Two people mentioned a bad wire under the radiator overflow reservoir. I checked the plugs that hook up to the ABS module and they all looked good. There is a "Pin Test" that exists that you can do with a multi-meter to check these plugs. Just google "ABS Pin Test" for the specific instructions. Anyway, this wasn't the issue.

7. The ABS Hydraulic Pump Motor: This is mounted under the ABS module and attached to the ABS system housing. When I was looking through the system for faulty wiring, I did notice that the two wires going to the pump a black and red, were not in great shape. I wiggled them and they seemed fairly stable, but they looked like they needed some love. I skinned them back about 2" where they meet the pump motor, and although they were connected, they weren't in great shape. I tested the red wire at the motor terminal for power and it had it. I then "jumped" the red to the black at the motor and tested the other end of the black at the harness plug and it was indeed pushing power through just fine. I then unhooked the truck's neg. battery terminal for safety. I cleaned the wires with elec. contact cleaner and then soldered them all the way to where the wires meet the motor housing. Sealed them with liquid electrical tape. Hooked negative battery term back up and tried the scanner, knowing this totally was going to be the fix. Still had the C1096 code. 1:30am and restless I called it a day and reflected on my life choices while laying in bed staring at the ceiling with visions of ABS pumps being smashed by giant hammers.

8. Replacing the Hydraulic pump: Epiphany in the a.m.!!! I decide that maybe my soldering job on the wires didn't work or maybe the pump motor harness had a bad contact or wire, or maybe the pump was just shot so I was going to replace the entire motor with the one I got from the LKQ junkyard as part of the $110 bundle of joy. 10 minutes to take the pump off, two small 7mm bolts. You have to bend the mounting bracket back towards the radiator to allow the motor to come off. I used a small pipe wrench to latch on and bend it back. I suppose you could heat it too, to make it easier. Anyway, I put the new motor on. Side note, there are little "bumps" (I'm assuming ends of pistons), that go into the hole where the motor shaft goes. You have to wiggle the motor a bit to push the shaft back in, which pushes these pistons back in their homes. Remounted the motor, bent the mounting bracket back. Hooked everything up. Air cleaner housing back together. Started the truck - LIGHT IS OFF. Project done. I'm going to Disney World!!!!!!

I'm sure there are lots of "oh, you should have done this first" comments that are ready to beset me, to which I will respond, "where were you when I was trying to fix this darn thing?", so let's just keep everyone happy and lay off the lectures. As my dad used to say, "I don't give advice, I don't take advise, I only tell you what I experienced". This was only my experience and I'm not diagnosing anyone's ABS issues.

I hope this helps if you have this C1096 ABS issue or the ABS light.

"What a long, strange trip it's been".

Cheers.

 

Great story! Sounds like I've been down that road before, though not on an ABS problem. And I definitely recognize myself in the part where you reflect on your life choices and have visions of smashing some part, or even the whole vehicle, with a large and heavy blunt object...

 

Glad to hear I'm not the only crazy with these visions from time to time, Skauber.

 

Nope, not here. We all realize that it can take serious troubleshooting at times to get to the root of an elusive issue.