Trifecta has me stumped... new module and good sensor didn't fix it

[377Z]

Using carly and DIS/GT1

Codes I am getting:

5EAD sensor front left line fault
5F29: pressure sensor, temperature signal error. Parity failure, transmission error
5F17 DSC: wheel speed sensor, front left, wrong type
6023 EMF: BY RDZ/BY POWER SUPPLY ? Operating element line 4 - line interruption (Message by DIS test sched is wheel speed sensor signal or value below threshold)
6044 DSC INTF EMF S2/KLEMM30G?Temperature sensor fixing motor right - short to ground

One of the test schedules is telling me to check the DFAVL line, yellow with red stripe, pin 35 at the module, that goes to the parking brake control unit (in the trunk at the parking brake mechanism). Seems random. Tested DFAVL line as good so that's not it. Swapped front speed sensors, previously only the left front wasn't reading a value in the diag part of DIS, after swap neither fronts read. Put the new ABS module in, no change. Swap front sensors back to their original positions, and it's back to reading all three other than the front left. So one problem is basically some issue with the front left sensor, AND line/circuit?

History: before the issue, the car was operating fine, all ABS/DSC/traction control?parking brake fully operational. I will note that the module was a repaired one, fixed the front left wheel speed sensor circuit and some other circuits (would have to look to get specific). Also, when I got the car the plug on the front left sensor crumbled, at the time of failure I had that connector cut out and lines soldered. Figured since the connector was bad I'd have to cut and replace anyway, and the sensor side isn't sold without the sensor. was operating like that successfully for over a year.

At the time it failed I was driving about 35 MPH normally in mild weather on a clear day. I suddenly felt the ABS buzz out of the blue for about half a second and the trifecta appeared.

Thinking its certainly the module, with all the bizaare codes popped all at once, and no other issues/symptoms, I figured the module went bad again so I bought a replacement. Sadly the new module didn't fix the issue. I suppose the new module could be bad but its all the same codes so pretty unlikely.

I did get a new wheel speed sensor, but was a Delphi from FCP. FIgured Delphi should be better than the Chinese ones. I was wrong, resistance test registers NOTHING. So, I cut the plug off and soldered it to my old sensor, since the only thing wrong with it seemed to be the plug.

I tried to check resistance of the wheel speed sensors at the module plug, but I can't seem to get any readings with my multimeter. I get like 0.5 or 0.6 at the sensor with the multimeter with it set to 2K. Didn't have a chance to pull other wheels and check the other sensors manually. Not sure what the issue is, but looking all the wheel speed sensors in DIS, the other three all register values. The front left doesn't with either the old repaired or the new module.

Oh, also checked all fuses associated with the ABS, DSC, and parking brake. All check out.

Can anyone shed any light on next steps you'd recommend? Has anyone ever had a wheel speed sensor actually go bad, other than the plug? Its just a magnetic hall effect thing, I can't believe anything would go wrong with it.

I'm stumped.

edit: Carly seems to associate 6023 and 6044 codes with the parking brake module, though DIS doesn't seem to, and DIS doesn't direct me to check the PBR module. This line is tied in to the front left wheels speed somehow though based on the TIS diag. could the signal be getting interrupted here? Parking brake still works BTW, just not as the emergency brake (no doubt this is why that module needs a speed signal).

[jclausen]

These cars are so complicated maybe a visit to a good independent BMW shop is in order

[377Z]

These cars are so complicated maybe a visit to a good independent BMW shop is in order

I think you are right, however I highlighted the hardest part of the suggestion

It is so hard to identify a good shop with the actual capability to troubleshoot vs. throw parts at something, from the places that just take your money. My experience has been that places just change parts until the problem is gone. If I knew there was some way to diagnose/verify correct function of each module (line continuity is easy) I'd have taken it in already...

One thing I know I need is a speed sensor. WIll probably buy a BMW one even though I don't get why non BMW ones are said to not work--its just a hall effect sensor, there shouldn't be any magic to it.

The balance of the codes seem to be line faults/signal/power related, some related to the EMF (parking brake module). Once I verify its getting the proper power supply I'll have to look if the software package I have can code modules. Perhaps I can buy a used EMF and give it a shot if so.

I've read that the wheel speed signal is used by other modules, in the diagnostic display of DIS you can look at that for the DSC, the left front is always dead. I might be able to look at that through another module, that could tell me something.

Other aggrevating part of this is I only have limited time during the week to spend on it, but I also don't drive it that much currently. But I want it fixed....

[billr99]

What kind of shape is your battery in? These things, like many new model cars, are really touchy on being in the proper current range. If the current gets toward the lower part of tolerance, you can get some weird errors popping up even though the car runs and mostly operates as normal. Also related, is the condition of the various grounds, some of which are down pretty low and susceptible to road slop.

Good Luck,

Bill

[377Z]

What kind of shape is your battery in? These things, like many new model cars, are really touchy on being in the proper current range. If the current gets toward the lower part of tolerance, you can get some weird errors popping up even though the car runs and mostly operates as normal. Also related, is the condition of the various grounds, some of which are down pretty low and susceptible to road slop.

Good Luck,

Bill

Thanks--funny I just re-registered the existing battery to be on the safe side. One odd thing I failed to mention, I only run DIS with the car running, and the car is at like 14V. Battery at rest is just over 12 (like 12.2?) However, as I'm opening DIS, it gives a message 'battery low connect a charger' which is odd because the car is running with the alternator going, and its putting out like 14V...

Mystery # 2?

Nice--I see you have Volvos too. I learned of the battery being an issue when low with my first S60R. Have a V70R now and a XC90 V8.

[billr99]

Thanks--funny I just re-registered the existing battery to be on the safe side. One odd thing I failed to mention, I only run DIS with the car running, and the car is at like 14V. Battery at rest is just over 12 (like 12.2?) However, as I'm opening DIS, it gives a message 'battery low connect a charger' which is odd because the car is running with the alternator going, and its putting out like 14V...

Mystery # 2?

Nice--I see you have Volvos too. I learned of the battery being an issue when low with my first S60R. Have a V70R now and a XC90 V8.

Wow, funny you should mention a V70R. I got rid of my '05 V70R after I got my 750i (wife says no more than 2 cars at a time!). It was my V70R that made me mention the battery thing. I chased an off-and-on fuel delivery problem that seemed to only occur when we had a high humidity condition from fog and/or prolonged rain. I replaced the fuel delivery module, fuel pressure sensor and was about to replace the pump, when VIDA came up with a marginal battery current condition. I figured it was unrelated but also figured that the battery had shorted a plate when we had had an unusually hot period a couple of summers ago. The battery's voltage measurements were all normal (i.e. 12.8 at the terminals not running, about 14.2 with the car running) Anyway, replaced the battery and the fuel delivery problem disappeared. I did have the battery load tested just to make sure and that is where it failed to produce adequate current. So as I said, its not voltage we are concerned with here so much but the battery's ability to produce adequate current to the 30-40 ECUs that these cars have.

Cheers,

Bill

[377Z]

Update to close the loop: I was able to fix the car. In DIS, all but the left front speed sensor would register values--for some reason LF wasn't reading. Previously checked continuity of the lines from the sensor to the ABS module plug and verified good, but swapping sensors LF to RF didn't work. I couldn't make sense of how these should be checked and what values they should register; I saw references to reisitance and diode tests, but would get erratic values for not only the questionable sensors but also the good ones (RF, LR, RR). One or two BMW specific YouTube vids said resistance check should be around 0.7 on the 2K scale, I wasn't getting a reading. Turns out I'd only get a reading in the 20M setting, which was out of the range of the other cheaper multimeter I was using previously. Also, the values were different for both resistance and the diode setting depending on polarity.

Each wheel speed sensor has a pin 1 and 2 at the plug. So, I marked which pins at the ABS module connector were pins 1 and 2 for each, and tested the other three sensors both for resistance and diode test with polarity both ways ( so four values for each sensor) to get an idea of what the LF values should be. I then resoldered the LF line (previous repair, that sensors plug had crumbled), ensuring I had pins 1 and 2 in the correct spots. Got it all back together with heavy shrink tube on the splices, figuring at least now I KNOW the module is receiving signal.

Since I had other bewildering signal/short errors I wasn't confident this alone would fix it--figured surely some are a result of the battery being on the weak side, but voila, startup and all the warning lights went out. F-in hallelujah! Will still replace battery soon.

also now have a brand new ABS module I don't need, likely too late to return but I guess there's always eBay.