ottawaguy2

2015 IS350 F Sport
Hopefully someone can help me diagnose this issue: I have replaced both rear hub bearings sucessfully making sure all things are handled correclty like
1. Make sure speed sensor does not get damaged.
2. Dust deflector get seated properly.
3. I took off the knunkles completely to make sure dust deflectors get seated propertly.
4. All the nut/bolts are torgued properly.
5. Replaced rotors/pads with OEM ones and make sure they are all installed correclty.
5. Make sure speed sensor are installed correctly.
However I am surprised at this issue:
1. On highway speed - I get all these warning lights on PCS, BSM, AWD, Brake malfuntion.
2. Over all brake funtion normally..
3. When going on below 90KM/Hour speed - warning seems to clear away itself and then they come back when above 100KM/Hour.
4. Some time I hear brake knocking in the rear when I try to use brake then the knocking goes away itself.
I am bit puzzled at all this strange behaviour - hopefully some kind soul can guide me and point me in the right direction.

kj07xk

You replaced just the bearings, not the whole hub, correct?

ottawaguy2

Whole hub on both rear side was replaced.

arentz07

I think that is the first thing I'd have looked at.

ottawaguy2

Rear brake knocking is the result of false ABS trigger.
What is next - I learned that may be speed sensor is dirty and causing this - I will clean up the tip of the sensor and see if it helps.

kj07xk

If you didn’t use OEM hubs, it could be the hubs.
See post #13 in this 2IS thread:
2IS thread

Also, if the new hubs don’t have the same number of cogs for the speed sensors to read, your front and rear measurements for your AWD vehicle will not match, and throw everything off.

You may have to check to see if you’re even getting signals out of the speed sensors (google how to test speed sensors).

ottawaguy2

Thanks for pointing it out but I always use OEM parts and thus I did use OEM hubs.
I took the speed sensor out from the hub - sensor tip was bit dirty with black anti rust coating in wheel well, I guess it touched the anti rust coat in the wheel well while hanging there.
I am going to test drive on highway today and hopefully the issue get resolved. I will update it later.

ottawaguy2

Cleaning the sensor tips of both side sensors did NOT resolve the issue. Not sure if it is a defective OEM hub. I am contacting the vendor to get a replacement.

truu

Have you also checked the wire for the ABS sensor and not just the sensor itself? I’ve had a similar issue and determined the exposed wiring caused the error. Places to check are at the metal mounting brackets which may chaff the wire over time.

kj07xk

Bummer. If you have (or have access to) an oscilloscope, you could look at the signal out of the speed sensor as you spin the wheel. Should see a sine wave. Put the sensor into the old hub and turn it, should see the same wave for the same rotation rate. No signal from the new hub, but have signal with the old, the new hub is bad. No signal in either case, the sensor is probably bad.

(If you don’t have an oscilloscope, just a multimeter should give you an AC voltage reading as you spin the hub.)

ottawaguy2

Since OEM hub is on back order - what other option is a good one? Thank you folks for all your time, help and support.