Without anything unusual happening the ABS light came ON and there is a STABILITY CONTROL FAULT dash warning

I charged the battery which tested good; and I checked master cylinder level which was full.

Then I disconnected the harness connector at the ABS unit, and reconnected

Ignition turned on and engine started / Everything Clear. No warnings

The I drive to corner, and the moment I braked the ABS Light and Script Warning immediately appear.

My question: First to check? Clean wheel sensors and then check for continuity to ABS unit?

Then Open ABS unit to look for broken solder joints?

 

Yes . On the 97 ? . The sensors will read about 1300 ohms as a fundamental reading . Don't try too hard to get the sensors out as mine are plastic on my X300 and I broke one .

 

Gordo, yes clean 1st. I had a bad wheel bearing cause this. Any play / noise in wheel?

John

 

If you are asking about the 97, the most likely cause after the sensors and harness is the solder connections to the abs pump pins. Removal of the module and repair is covered in the DIY Sticky and at jagrepair.con

 

No the bearings are quiet and no play in wheel.

I am having a difficult time reading ohms on both the ABS and the sensors themselves after removal.

I get wonky readings between nothing and 1900. If you connect the meter the readings should stabilize and opposed to pulse, correct?

I'm using an Actron cp7678 which is a standard automotive meter. And the probes are clean and polished.

 

Should be stable . Test a light bulb to see if it's the meter .

 

Thanks.. It's the meter. Erratic readings on the base of an incandescent light bulb.

Lasted twenty plus years, but can't use it as an ammeter any longer.

Bought a new one. Works fine. Thx

 

Just use the meter to check resistance. Should be 1000-1200 ohm. If you connect at the plug to the module and move the cable in the wheel well you should see if there is a break, which does occur sometimes after years of flexing.

 

All sensors were pretty clean. I'd removed them when the calipers were pulled for new discs and pads about 10k miles ago. There was no build of of crud; just a slight film to wipe off. The Sensor Connector pins and the Harness Sockets appeared clean w/o corrosion.

Likewise the transducer rings look clean. How do you reach the rears to brush off?

My Question:

All the ABS sensors readings range between 805 and 820 ohms at both the sensor terminal pins; and the ABS plug terminal sockets. A couple of posts cite ohm readings as either 1000 ohms or 1300 ohms as normal or acceptable.

I'm thinking all are within a very tight range of resistance, so I'm probably OK as far as sensors and harness wiring. Or is there a minimum reading to replace?

I'll remount the wheels and test it. If light comes on... Then ABS module? Correct?

 

Is a reading of 810 to 820 (on all sensors) too low? Do we know if there is a minimum resistance?

 

The wisdom on here indicates 1100 ohms, with the spread given by RJ. Could it be your meter be reading low? If they are all showing the same value I doubt you would be unlucky enough to have all four fail at the same time.

I cleaned out the rear reluctor rings with a flat-bladed screwdriver; it's a bit tiresome and there's prbably a better way, but I didn't have to crawl under the car.

I'm surmising here, but I imagine that the if the ABS module has the 'resolder pins' problem it would flag a fault as soon as the brakes were pressed even while stationary?

When I had this issue I managed to pull the C-code for the offending sensor location just with Torque Lite, although I gather it's not supposed to work...

 

I have repaired the solder connection in several modules. In most cases the light would come on after driving a hundred feet or so, but sometimes when the brakes were applied. The ECU detects the fault but doesn't cause the light to come on until it repeats. This is the most common issue I have seen with the early X100 and even X300 modules.

Testing with Autoenginuity or some of the newer readers on the market the code C1095 identifies the connection to the abs pump as the problem.

A resistance of 810-820 is probably an error of the meter like michaelh says, and not a problem.

 

I would think if all 4 sensors read the same value you couldn't have all 4 bad

There was a change in the Teves ABS sensors from inductance to hall effect ( ? ) somewhere in models and years .

For a functional test you can spin the tire with the meter on A/C voltage and should see it respond with less then 1.0 volts .

The light won't reset until reaching 12.5 MPH

The light won't appear until 3 events ( I beleive )

 

I found this article. I assume our cars are using inductive sensors for the ABS.

the author cites a range of 500 ohm to 1500 ohms is usually OK for ABS sensors. So maybe my 800 ohms are acceptable. He also goes on to describe testing techniques, including testing for voltage while spinning hub (tire) on the car using a volt meter.

https://www.linkedin.com/pulse/induc...iril-mucevski/

 

My 2 cents worth...my ABS light and ASC/Traction Control Warning would come on erratically but over time more often. {I think if you have continuity between the harness pins on the connector ( have someone jiggle the sensor leads to verify no breaks) then you probably have dry solder joints.} I finally decided to open the box and sure enough, there were cracks or dry joints. I elected to disconnect the 4 lines going out to the brakes, because I didn't want to bend the lines and have to live with them afterward. Also unbolted the 4 mount bolts to allow easier removal of the controller from the manifold. Re-bleeding the ABS manifold is no problem, just like a regular brake bleed (suppose to change the fluid periodically anyway). I drilled a 1" hole with a hole saw in a drill press right over the pins. A 1/2"-3/4" hole saw would have been enough/better. Fixed, done, no more issues. {Apparently other issues can crop up with the ABS Controller according to some of the experts here; but at least this problem will be rectified.} I epoxied a cap over the hole. Brake lines still nice and straight.

 

As expected, the problem was sourced to bad solder joints in the ABS Module. Sent the unit to Module Repair Pro in CA. Quick turnaround and back fixed in six days. $49 repair shipping USPS Priority mail back and forth another $35,

Be advised that when the repaired module was replaced all the brake related lights and warnings cleared automatically. However, I still had to manually clear the check engine light. So don't freak out thinking the fix didn't work.

Also I noted when the module was out, the car was completely driveable. However, the dash is filled with lights and warnings; you don't have a working speedometer; and obviously no ABS. Otherwise using the car is not a problem.

Thx for all the help. Gordo

 

Well done. Always glad to hear when a bit of re-soldering fixes a flaky ABS module or brake pedal switch. The re-soldered brake pedal switch on my wife's 2006 XK8 has performed perfectly for more than a year now, and I have a spare re-soldered one just in case....

 

I may have the module solder problem in my XK8.

Checked and cleaned Sensors. All are about the 1100 ohms
Just need to know how to get the main connector off the ABS module.
How does it unclip??
I will then be able to check the resistance of the sensors at the Module connector.
If all is well there, then I will have to tackle the module itself.
Thanks

 

There are two connectors. Facing the engine bay, they're on the right side of the module. The main communications connector is on top, with the electrical power source plug, hidden underneath.

The main is removed by first pulling up on a locking device type handle. It is located on the top of the connector. When it is pulled upwards, it unlocks the two sides [eg. pins into their sockets], and separates them by 3/8th of an inch. This handle must be actuated in order to remove the top connector.

Once the main com connector is pushed out of the way, you can see the power cable connector. It is held in place by a barb fitting that is pushed inward as you pull the connector.

Both of mine were in there pretty tight and I used some electrical connector compatible spray lube before applying any force to separate them. WD40 would work too. Jiggle them around to work the lube into the mating surfaces.

Good Luck.