4x4 + Brake + ABS lights + sluggishness...then "clunk" and Trans Safe Mode Program

[Porschesolutions]

Ok are they easy to get to and could they be contaminated by axle grease? My car is getting it's second front axle (right side...left was done 2k miles ago as they both failed about the 100k mile mark..thanks BMW).

Mark

[TerminatorX5]

first find out which speed sensors are acting up, and if they still are acting up... once you know which ones are bad (if any), get the OE sensors - we had a few members here going with aftermarket sensors, just to find that the quality was sub-par, and eventually going for the OE.

To remove the sensor, you will need i think an allen wrench, i think metric #6 or so... don't hold me against these tools, but the removal of the sensor is rather simple, you take the wheel off, stick your hands in the back of the wheel hub and at 12 o'clock there should be a hole, which can be all gunked up, and in the hole there is a screw that holds the sensor - you can trace the location of the sensor by tracing the wire that is coming into the hub (all 4 wheels have a speed sensor, and only front left and rear right have a brake pad sensor, so in those locations you will see two sets of wires).


keep us posted of your progress

[Porschesolutions]

dunno if they were acting up or just a residual from my voltage spikes...will have to drive it with the new alternator & all codes cleared & then check again. Is there an Ohm value or such that can be checked to see if they're actually failing? Could thrown CV grease be causing a weak signal?

Mark

[TerminatorX5]

the sensors are Hall effect sensors, they should react to OhmMeter as a diode - if you know how to measure diode values...

the gunk may have issues with the readings but the unit is sealed, and reacts to magnetic field - so, if the physical distance is increased due to gunk, or the gunk has metal/magnetic properties, then the reading could have been affected. however, the contacts may become corroded and that alone can present an issue - this is the reason that the connector is watertight and sits in the fixed enclosure in the wheel well...

drive around first, clear the codes, drive again, see if new codes are there, and then you can determine if the sensors are bad...

[Porschesolutions]

34526771704

this speed sensor? Rockauto has them for about $57 each. I'll look at OE sensors too.

[TerminatorX5]

this part is for the front wheel, $62 each from BMW of Fairfax + shipping of $9 if order is under $150. seems like a no brainer to me...

[HEISING]

If your alternator is hitting 17.3 Volts, thats definitely a problem. Replace the alternator and see if your problems disappear.

[upallnight]

I brought my last wheel sensor from O'Reilly Auto. They were local, have them the next day and they come with a lifetime warranty. I brought some genuine BMW wheel sensor from a reputable BMW reseller, but they sent me the wrong one. When I told them that the one they sent me didn't look at all like the one I removed from the truck, they said that according to their computer the one that sent was the one for my car. I google the part number that was on the box and found out that they sent me a wheel sensor for a 2005 X5, I have a 2001 X5. They accepted the merchandise back but I was out of the shipping cost both way which was about 25 bucks.

[Porschesolutions]

Ok the regulator on the alternator was bad: replaced with a rebuild unit and it's much better: battery does not 100% charge now (on my charger, left over night last night) as I had a light & a fail-safe last night (over 100d here now) & felt all the electronics + blower/AC on full might have taxed the electrical system. Ok so far today, BUT, I pull away from a light after sitting in traffic for 1/2 hour only to see blue smoke out the back. Wife dropped me off at work and again as she pulled away; blue smoke!

It's hot and I'm using the Castrol/BMW Synthetic 5w-30 as recommended...with drain & switch to 5w-40 Mobil 1 High Mileage as per other thread posts and will order/check the CCV's too. :/

Wife not thrilled, can't say I blame her.

[Porschesolutions]

Ok I bought 9 quarts of Castrol 5w-40 last night and noticed that my mechanic "topped me off" where now at 4 days later with my oil temps less than 200d, I'm about 1/8" over the Max part on my dipstick: very good chance I'm over-filled. My 25yr-experienced mechanic had no idea that oil expanded when hot and that the Max level on the dipstick should not be reached except when the vehicle is at it's maximum operating temperature.

This is air-cooled Porsche 911 information as the dry-sump tanks & subsequent oil level should only be checked with the engine idling, at max temperature, on flat ground.

Mark