ABS sensor replacement didn't work

hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

When the mechanic replaced my left ball joint, he accidentally broke the ABS sensor when trying to take it out. He had another ABS sensor from a Grand Cherokee and replaced it with this other one instead. It looked totally similar but it was a right one, not a left one so the ECU didn't recognized it and the ABS light on the dashboard immediately showed up.
I purchased a new left ABS sensor for the Liberty and today I replaced it. I went for a ride but at first it started to make the ABS brakes malfunction. Every time I hit the brakes, it sounds like a machine gun and makes a little shake on the front left wheel. So it is like a vibration and then it brakes. After doing that for a few blocks, then it stopped and the ABS light showed up again on the dashboard. Now it doesn't vibrate anymore everytime I brake, or it only occasionally does, but instead I have constantly the ABS light on. When I brake and it vibrates, the ABS light goes off. What could it be?

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joe_ · **Posted:** Thu Sep 21, 2017 8:35 pm

When you brake and it vibrates, that's the ABS system thinking that a wheel is locked up. It starts pulsing the brake pressure to that wheel to try to regain traction.

Then the system eventually decides there's something wrong with that sensor, disables ABS, and turns on the warning light.

Make sure the sensor is correctly seated, and check the wiring for breaks in continuity.

tjkj2002 · **Posted:** Thu Sep 21, 2017 10:10 pm

Some aftermarket ABS sensors are very different then the OEM ABS sensors and only work in there respective wheel bearing assemby.

If you still have OEM bearings you need a OEM sensor.

hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

I purchased the OEM ABS sensor from Mopar. I purchased it from idparts and this is the description:
ABS Sensor Front Left (Liberty CRD)
OEM Mopar

OEM Part Number: 52128695AE
Manufacturer Number: 52128695AE:

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hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

joe_ wrote:

When you brake and it vibrates, that's the ABS system thinking that a wheel is locked up. It starts pulsing the brake pressure to that wheel to try to regain traction.

Then the system eventually decides there's something wrong with that sensor, disables ABS, and turns on the warning light.

Make sure the sensor is correctly seated, and check the wiring for breaks in continuity.

Are you saying the mechanic didn't fit it well? He said it was plugged in ok.

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flash7210 · **Posted:** Fri Sep 22, 2017 8:38 am

joe_ wrote:

When you brake and it vibrates, that's the ABS system thinking that a wheel is locked up. It starts pulsing the brake pressure to that wheel to try to regain traction.

Maybe the "sensing ring" inside the hub broke loose and is just bouncing around inside the hub?

hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

flash7210 wrote:

joe_ wrote:

When you brake and it vibrates, that's the ABS system thinking that a wheel is locked up. It starts pulsing the brake pressure to that wheel to try to regain traction.

Maybe the "sensing ring" inside the hub broke loose and is just bouncing around inside the hub?

And if that is the case, what should I do?
Thank you

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hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

I ve seen a few videos about ABS replacement and it gave me the idea that maybe what happend was that when the mechanic broke the original ABS sensor he left half of it inside the hole and probably there is still some debris inside that needs to be removed with compressed air... could this be?

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flash7210 · **Posted:** Fri Sep 22, 2017 8:58 pm

If pieces of old sensor did break off and get stuck inside, there is no way to get the pieces out. They are stuck inside the hub. You would have to replace the whole hub assembly.

hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

flash7210 wrote:

If pieces of old sensor did break off and get stuck inside, there is no way to get the pieces out. They are stuck inside the hub. You would have to replace the whole hub assembly.

When the mechanic tried to take out the ABS sensor to replace the ball joint, the sensor broke in half and I don't know where did that go. I'll have to ask the mechanic but one thing I know for sure is that he didn't use compressed air to clean up the hole before putting in the new sensor.

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hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

Any idea?

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hgrimberg · **Joined:** Mon Dec 19, 2011 11:03 pm **Posts:** 363

I took out the new ABS sensor again and then cleaned the hole in the hub assembly very careful. Also checked if some debris or part from the old broken ABS sensor was left inside but there was nothing in. The problem is that when I start driving, and try to brake, the brake starts to shake and doesn't stop the car immediately, instead is like It slides and then brakes. After about 2 or 3 times of braking like this, it stops doing it and the ABS light on the dashboard comes up. I scanned the ECU using a real Chrysler scanner with ABS support and it doesn't detect any error code. I also cleaned all codes but with no avail. What could it be happening?

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ABS sensor replacement didn't work

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