ABS errors after changing suspension

[JeyLn]

I had coilovers for years but had enough of the stiff ride and feeling everything and decided to go back to OEM.

When installing the rears I had trouble getting the subframe to lower enough to fit the spring on the left side, thats when I noticed the abs cable was stretched on the part that is fixed to the subframe back to the body and was stopping me from lowering it enough. I watched many videos even checked the workshop manual and no one ever mentioned having to unplug the cable from the brackets so it is free.

How I didn't notice that it was stretching ?
The cable on the right side is longer and does not stretch at all when pulling down the subframe but for some reason on the left side it is already stretched almost to the max just by jacking up the rear.

I don't know if they were made with different lengths but they have the same part number but the right side was made on 2009 (weird?) and the left 2013, which was when the car was made.

On the front it was a nightmare because you have to remove the hub due to the length of the strut compared to the coilovers I didn't remember it was this difficult.
Lots of anger and pain because I couldn't align the CV axle splines inside the wheel bearing. But in the end I managed.

Went for a test drive, as soon as I get out of the garage, brake pedal starts vibrating and going back and forth as I'm pressing it, speed needle goes crazy jumping to 50 then to 10km/h, rpm start jumping too.
Then the abs, esp and tire lights turn on.

Great, one more f*** up on my miserable life.
Scanned for errors, front and rear left wheel speed sensors range/performance and mechanical fault.

Watched some live data and those sensors are intermittently working as intended, sometimes spiking between 0 and the correct speed and not working at all.
Sometimes cutting power abruptly that it feels like it's braking by itself at low speeds. When the car is stopped, sometimes there's spikes like the sensor is sensing speed .

I already inspected and wiggled the cables to see if it's a broken wire inside but it doesn't make a difference.

Please help, should I just buy new sensors ? There's no apparent damage to the cables both on the front and rear although the rear was stretched as I mentioned.

[amer6R]

If you didnt unplug the abs sensor cable from front hub it probably got damaged. This also happened on my car when mechanic shop was putting lowering springs...

On mine car the speedo worked fine with one of the abs sensors out of operation.

[JeyLn]

If you didnt unplug the abs sensor cable from front hub it probably got damaged. This also happened on my car when mechanic shop was putting lowering springs...

On mine car the speedo worked fine with one of the abs sensors out of operation.

I did unplug at the front so I'm not sure why it shows the same error as the rear.
The rear I know it may have damaged the wires inside, I still have to look with a multimeter but at the front I don't know why it suddenly isn't working too.
The front shows much bigger spikes in readings I think that's the one cutting the power and jerking the engine.

[amer6R]

The rear is probably good.
If you need wiring diagram for abs pump connector so you can check the continuity let us know what model of abs pump you have.

Make sure you store your abs long coding if you are going to unplug the abs connector.

You can jack up the car ( make sure its fixed) go to live data for wheel speed and spin the wheels see if the values change.
Just make sure the car is safely secured.


There is also a electromagnetic ring on the hubs- bearings maybe you might have damaged it when trying to insert the cv axle. I highly doubt in this.

If you unbolt the ball joint you get the space to insert and remove the cv axle. ( if you can mark the nut position from the bottom so you can return them to the same place ( alignment)

[JeyLn]

The rear is probably good.
If you need wiring diagram for abs pump connector so you can check the continuity let us know what model of abs pump you have.

Make sure you store your abs long coding if you are going to unplug the abs connector.

You can jack up the car ( make sure its fixed) go to live data for wheel speed and spin the wheels see if the values change.
Just make sure the car is safely secured.


There is also a electromagnetic ring on the hubs- bearings maybe you might have damaged it when trying to insert the cv axle. I highly doubt in this.

If you unbolt the ball joint you get the space to insert and remove the cv axle. ( if you can mark the nut position from the bottom so you can return them to the same place ( alignment)

I rotated both wheels, the front one doesn't give a reading at all. The rear gives readings with spikes or intermittently, after a few turns the dash light up again with only errors for the rear wheel speed sensor.

I measured resistance on the front sensor and it's giving zero resistance, shouldn't it give some value ?
Is it safe to assume it's defective ?

EDIT: I removed the front wheel speed sensor, no damage, cleaned as there was some gunk, re-measured resistance and now it gave 4.166 ohms. No idea why it was giving zero resistance before, the tips were on the pins the same way.

[JeyLn]

I measured DC(?) voltage across the 2 pins connector of the abs cable and it's giving zero voltage. I think I found the problem, somehow it broke even though I disconnected first before removing the strut. How more lucky can I be ?

Meanwhile the rear is giving crazy readings just spinning by hand.

[amer6R]

Since the sensor has some resistance ( its not open) it should be good.

What do you get when you compare it to other side?
Voltage, and wheel speed...

If you measure on all 4, and graph it.
The Sensor with bad connection wil periodically show on the graph, if its has no connection it won't show at all.
and the speed souldn't be so much different.

the fastest method is to compare values since you have access to 4 sensors.

[ciclo]

According to erWin.

Installation:
– Before inserting the speed sensor, clean the inner surface of the hole and coat the speed sensor all around with high-temperature paste G 052 112 A3.
– Insert the speed sensor into the hole in the wheel bearing housing and tighten the bolt to 8 Nm.
– Connect the speed sensor to the speed sensor wire.
– Turn the steering wheel to full left and right lock and check the speed sensor wire clearance (front speed sensors).

The same applies to the rear axle speed sensors.

In relation to coil springs (summary):
A spring compressor should always be used...


If you need to repair a speed sensor wiring harness, it's best to replace it completely from inside the vehicle... or have appropriate tools and materials for an "easy" repair.



These are just small details to keep in mind that will make a difference in our miserable, and sometimes fun lives. Over time, overcoming setbacks makes our lives take on a different meaning.

[JeyLn]

Since the sensor has some resistance ( its not open) it should be good.

What do you get when you compare it to other side?
Voltage, and wheel speed...

If you measure on all 4, and graph it.
The Sensor with bad connection wil periodically show on the graph, if its has no connection it won't show at all.
and the speed souldn't be so much different.

the fastest method is to compare values since you have access to 4 sensors.

I can graph it and post it here.

Yesterday while I was fiddling with the front sensor, I checked the pins, pulled back that rubber grommet, the pins are correctly inserted to the connector and the wires look fine. I thought maybe when the coilovers were installed years ago the mechanic stretched the abs cable and now when I took it off, somehow it was enough to create a bad contact or something.

Thing is I plugged it several times and it started working again, I spinned the wheel and it's registering speed, still have to test drive though.

I haven't compared resistance with the other side yet but the rear left is measuring 0.748 ohms, a little bit low I think?

[JeyLn]

According to erWin.

Installation:
– Before inserting the speed sensor, clean the inner surface of the hole and coat the speed sensor all around with high-temperature paste G 052 112 A3.
– Insert the speed sensor into the hole in the wheel bearing housing and tighten the bolt to 8 Nm.
– Connect the speed sensor to the speed sensor wire.
– Turn the steering wheel to full left and right lock and check the speed sensor wire clearance (front speed sensors).

The same applies to the rear axle speed sensors.

In relation to coil springs (summary):
A spring compressor should always be used...
If you need to repair a speed sensor wiring harness, it's best to replace it completely from inside the vehicle... or have appropriate tools and materials for an "easy" repair.
These are just small details to keep in mind that will make a difference in our miserable, and sometimes fun lives. Over time, overcoming setbacks makes our lives take on a different meaning.

I actually have one of those compressors but I didn't use since it was too cumbersome to use when working on the ground, the shaft hits the floor.

I have to show you this, as you can see the right side abs cable has lots of free wiggle room left.


But the left side, the car is just jacked in the air, the cable is already stretched with like half a centimeter of wiggle, no wonder it's so easy to damage.
How is this possible ?
And the fact that one cable is from 2009 and other from 2013 makes me think something fishy happened before I bought the car.


While inspecting the rear abs ring I noticed some metal particles could this cause the erratic readings ?

[ciclo]

Hmm... for example, if a vehicle's manufacture date is June 2013, all of its components are manufactured in June 2013 (+/- 15 days).
2009...what? ...that vehicle underwent a "cheap" repair. Inspect the entire line up to the interior; you may find bad splices or something similar there.
Maybe when someone installed that left wiring they forgot to take into account the maximum distance the axle arm travels and 'now' with a simple maintenance job it has been damaged.

Yes, metallic particles could also be disturbing the magnetic field detected by the sensor, causing it to send strange data. It is not decisive but it could happen.

With inspection and a little cleaning, it may be possible to move towards a solution.


... thanks for the images, they always help a lot.

[RUM4MO]

I think that you should unplug all 4 wheel ABS sensors and measure their DC resistance, I'd expect that they should all be roughly the same, that quoted measurement of 4.???ohms seems to be very low, ie coil winding short circuit.

Then, still with the ignition OFF, "look back into" the 4 wheel sensor connector and measure the DC resistance, they will each probably be different, but not by much - doing this will quickly let you know if the wiring and input channels of the ABS controller are all "okay".

Edit:- make sure that you are using a high impedance digital multi meter to do this work.

[JeyLn]

Tomorrow I will look at it again. The weird thing is the right side is the one that is longer or atleast looks longer, slightly different routing, is the one from 2009 but it looks original.

The left side is from 2013 (cars year) and when I checked the cable route the problematic part is between the subframe bracket and the body bracket where it is fixed with those ring rubber grommets, it's like that part was made too short. The entire wire looks original, interior it looks original, with foam on top of it, doesn't look like it was fiddled with. But it is strange. Maybe they made it with incorrect measurements at the factory? Highly unlikely though.

About the bearing I used a few q-tips to clean the surface, tomorrow I will test if it made a difference.

EDIT: There are 2 manufacturing dates on the harness stickers, due to the angle I only saw one of each, the first date is from 07-2009 and the second 02-2013, reference 6R0 927 904 D for left, 6R0 927 904 E for right side.
My fault for not seeing it.


the area circled is where the cable is too short.

[JeyLn]

.

The front left was 4k,166 ohms and the rear left 0.748 ohms.

One question, shouldn't the resistance readings be done with battery off ?
I remember I read somewhere it should be done like that otherwise it will damage the car electronics?

[ciclo]

So everything seems to be correct as far as identifying the wiring for the rear ABS/speed sensors:


Interpreting this conundrum/enigma another way, and according to erWin, there are several reasons why a 'new basic setting' of ABS system should be performed, among which may clearly be the maintenance procedures you performed. Do the basic setting of ABS system.

On the other hand, with the correct pressure in each wheel, in addition to the basic setting or ABS system, tell the system that the pressures are correct using the SET button in the glove compartment (press-hold, to beep).