Wheel Speed Sensor "Air-Gap Excessive"

Omerta · #1 01-28-2018, 03:14 PM

I have replaced the front drivers side wheel speed sensor with an OEM brand quality part. Cleaned out the hole and reinstalled.

I cleared all the codes in DIS and verified that the speed is indeed matching those of the other wheels when moving.

"Wheel Speed Sensor Air-Gap Excessive" still persists, this is cascading into my EHC2 and giving the trifecta error as well.

The wheel bearing and axle was replaced 3 yrs ago.

Any theories on the cause? ABS module or EHC2 module? I did have water ingress issues from the sunroof drain vents in the summer - but the system functions fine. If I clear the codes and do not move the vehicle, the air suspension system functions perfectly. I've rebuild the compressor and had no issues doing a leveling operation.

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80stech · #2 01-28-2018, 11:36 PM

Are you saying the code was there before you replaced the sensor?

andrewwynn · #3 01-29-2018, 01:55 AM

Swap sensor other side determine if problem is the sensor. If problem migrates it's the sensor if not then best chance it is a dirty connector

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brucemillar · #4 01-29-2018, 02:56 AM

Did you have to drill out the old sensor? I had a similar issue (trifeca and air gap) on my older 5 Series. It turned out that in drilling out the old sensor I had scratched the surface of the wheel bearing/reluctor ring. A tiny almost unnoticeable scratch, but that was the cause. The cure was a new wheel bearing. I have also read, of others "adjusting the air gap" by inserting thin washers to raise the sensor. That may be worth a try before opening your wallet to more abuse.

What suspension errors are you getting?

I also just went through a hellish problem on my HHCII - Error 116. I also rebuilt my compressor, using the www.bagpipingandy.com kit. I had to order a new cylinder bore and clock springs etc as well as the piston ring kit. My Compressor drier was all rusted up inside the drier can that is attached to the motor. When I took it apart there is a 'pepper pot' filter plate that had rusted up restricting air flow. Andy does supply a full kit that includes all these parts. Once I did this my suspension re-set and re-calibrated itself AFTER I cleared the error 116 using inpa. Some three weeks on and it has not returned..

Omerta · #5 01-29-2018, 05:41 PM

Quote:

Originally Posted by 80stech

Are you saying the code was there before you replaced the sensor?

I didn't have the proper software at the time to drill down to what error it was beyond identifying the corner.

The removed sensor was broken at the flange that holds it in place. The bolt broke off when I removed it originally and I held it in place weakly with a metal bracket until I got a new sensor.

andrewwynn · #6 01-29-2018, 06:07 PM

Did you get the bolt out so new one is properly oriented? My car the bolt broke but it worked "press fit" until it didn't. When it for a little loose strange stuff happened (abs kick in on dry cement) it could do that a while (like 20 brake applications before abs would shut down).

I have a nubbin of the original bolt that keeps it aligned.

After about the fifth time it worked loose I wrapped it with Teflon and pounded it in (gently with wood hammer handle) and it's been working most of a year since.

If yours still has no bolt take it out wrap with Teflon and make sure the angle is perfect.

Omerta · #7 01-30-2018, 12:36 PM

Quote:

Originally Posted by andrewwynn

Did you get the bolt out so new one is properly oriented? My car the bolt broke but it worked "press fit" until it didn't. When it for a little loose strange stuff happened (abs kick in on dry cement) it could do that a while (like 20 brake applications before abs would shut down).

I have a nubbin of the original bolt that keeps it aligned.

After about the fifth time it worked loose I wrapped it with Teflon and pounded it in (gently with wood hammer handle) and it's been working most of a year since.

If yours still has no bolt take it out wrap with Teflon and make sure the angle is perfect.

The head broke off the bolt, so I bought a new one and extracted the rest and cleaned up the threads with a tap.

The new sensor is very firm to place in the hole. I didn't remove any of the surface beyond a bit of surface rust so I can't see it changing that dimension.

I'll try swapping the sides - I was nervous of breaking the bolt on the pass side but we will see. I'll also borescope the hole and give the wheel a spin. Doubt I'll see anything but worth a try.

andrewwynn · #8 01-31-2018, 11:28 PM

What you may see is that some debris got in there and dented your sensor ring. Breaking the bolt seems pretty likely but short term (or long term in my case) you can get away with a press fit as I am so swapping is the easiest way to determine if the sensor or the bearing is at fault.

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