Afternoon,

This morning I tried to replace the N/S front ABS sensor, but the old one fell apart as I did. It broke by the wiring connector and by the nut hole, leaving just the magnetic bit stuck in the hole.

It looks like it's melted in there or something but I'm not sure how. Drilling it out didn't work, now I just have a mess of plastic.

I assume I'll now have to get a replacement part that the ABS sensor is screwed in to - does anybody know what that's called so I can order one from a breakers ( and get a pro to fit it )

 

The abs sensor does not screw into anything. It slides into the hole and the bolt holds it in. Once you chip the old one out the replacement dose not require professional help.
I am going to guess that a prior owner was unable to remove the sensor and applied heat, melting it in place.

 

The Wheel Speed sensor fits into a hole in the suspension vertical link (circled in red) and is secured by a single hex bolt. The Sensor should be a sliding fit but years of road dirt etc can seize it in place.



Provided you have successfully removed the hex bolt and disconnected the electrical harness, you can be quite brutal in breaking out the old sensor.

Graham

 

If it has melted in, any suggestions for how to get it out? I've tried drilling it out but didn't have any luck.

If I can't get it out I'll get my local garage to replace the vertical link, but I'd rather avoid the expense if anybody has any better suggestions.

 

It's plastic. Take a small cold chisel to it, then clean the hole with a round file.

 

You can get flat tipped drill bits.

There is also the old standby Dremel.

Like RJ237 says ... its plastic, so poke, prod, pick at it until all the little bits are out.

 

+1 to the various attack tools suggested.

If it's melted in, some localised heating with a gas blowlamp will soften it up again to aid removal.

Replacing the vertical link is OTT as a solution and will be $$$ costly.

Graham

 

I realised if I turned the wheel I'd be able to get better access, so after an hour of drilling and hammering in a screwdriver I got it out.

The new one is in now, but it's still giving me the 'traction control failure, stability control failure' errors, with the ABS light, immediately after starting the engine. Before I swapped the part, it was intermittent.

Could this mean the codes need clearing because it thinks somebody has nicked the sensor, or have I caused more problems? The new one is definitely plugged in properly. I don't have my own code reader yet so I can't just try resetting the codes.

 

I think it is mentioned somewhere that the codes can self reset once you have driven at greater than 5mph. It might take a couple of trips.

 

The yellow ABS icon would stay lit until the car is driven, but the "traction control failure ... " message should not appear upon restart if a good sensor is now in place, and if there is not some other problem.

One thing to check: there were two vintages of sensors, with different impedances. Are you sure you got the correct one for your MY?

Good luck.

 

I'm not sure if I got the correct one - I got it from an online breakers yard and relied on the website / breakers to find a matching part. Is there any way to tell, such as by codes on the part?

 

If you have an ohmmeter, a good test would be to compare the impedance of the new sensor to the other three. As I recall, the two sensor types had values of about 1k ohms and 2k ohms.

There is a procedure showing which pins on the big connector at the ABS module can be used to measure each sensor's impedance. I'm sort of on the fly this week , but maybe someone here can point you to that procedure.

 

This sheet from jagrepair.com has the pins. A lot of other info there, also.


http://jagrepair.com/images/AutoRepa...heet%20XK8.pdf

 

The resistance for your car should be 1000-1100 ohm, not the 2000 mentioned in the test sheet.

 

One other thing to check is the harness link lead - if it was making intermittent contact before the disturbance may have caused it to break completely .

 

That's the advantage in checking the resistance at the pins, per the abs sheet from Sam. It should be noted though, that there have been reports of cables that appear okay when the wheels are straight, but have breaks that show up when turning or flexing on bumps.

But my bet is that the solder joint for the pump pins has failed.

 

[.

But my bet is that the solder joint for the pump pins has failed.[/QUOTE]


That's my bet as well.

 

I think it's fixed itself. Thanks chaps.

 

It's been mostly fine since I posted this, but I've found that the error does re-occur when I reverse around a corner.

This has happened enough times now for me to think that it's not a coincidence. Any suggestions why that might cause the fault? Turning the engine off+on fixes it.

 

This is classic front-sensor-problem behavior. The hard turning input stresses the wiring and connectors leading to the front sensors. Look to cleaning and reseating the connectors, and maybe re-doing the zip ties that secure the wiring to the control arms ... so as to provide a little more slack at the sensor end. Another trick is to very slightly bend the pins in the sensor connectors to achieve better contact there.

Edit: forgot ... could also be a broken wire in a front sensor wiring section, but let's try the easier fixes first.

Once a fault has happened, even if only for a moment, the fault message will stay there until the car is re-started.