[Hov5]

Hey all,

I'd like to start off by saying I am new to the forums because I'm new to BMW. I love my car and it had very few issues at the time of purchase. This one was caused by a dumb decision by myself capped off by a detailer who messed up (going to be talking to him next week in person)

Everything had been FINE mechanically and cockpit-wise as far as lights go. After I got the engine bay washed, I started the car, seemed fine...shortly after, I got the ASC and ABS lights and my tranny (auto) started to behave oddly and eventually went into "limp" mode with the EML and tranny lights intermittently coming off and on coupled with the oil temp gauge shooting up to the max (which seems to have inspired the former). Pulled over, popped the hood, figured it might need some time to dry out. The engine seemed very...shiny. Almost like there was tire shine or some sort of cleaner that wasn't fully cleaned off still left on it. Or it could have just been a side-effect of whatever he used.

Dried some areas by wiping, got back in, same issues persisted as above.

Pulled over again, jumped online and searched. Quickly came across multiple threads that are available here (have read through many of them extensively, I promise), which somewhat saved me because I figured out I could simply unplug the module and drive that way until I figure it out (THANK YOU!) -- water came dripping out of the connector when I did this. The water was a browny colour - could simply be dirt mixed in, but there was definitely water inside the connector.

After I let the connector "dry out" with it disconnected for a couple days, I reconnected it (today) and there was absolutely NO noticeable difference than when I had it unplugged immediately before. Drove 300 km and still, no change.

Saw my indy today, OBD II scan came up with communication errors for a few different things, but among them were transmission and anti-slip system. Cleared codes, engine light went away, drove for a few mins, came back (ASC and ABS lights have never cleared at all). Scanned again, same result.

Taking it a step further, my indy's scanner was not at all able to communicate with the ASC/ABS module - simply nothing.

--- PURCHASED CONFIRMED-TO-BE-FUNCTIONAL ABS MODULE FROM A REPUTABLE SHOP RECOMMENDED BY MY LONG-TIME INDY MECHANIC AND REPLACED IT ---

I am WELL AWARE that coding is needed for replaced modules - but I am also well aware that, electronically speaking, something should be communicating with a working module, whether or not it has been coded (this just seems logical but PLEASE advise if I'm off base). The results were EXACTLY THE SAME - it is as if there is no module connected at all. Took it a step further and used an actual BMW reader that his neighbour has (forgot model and software details, will ask mechanic next week). Read everything, and showed a few different ECUs without any communication - vertical headlight adjuster (lol), a few others, and the ASC ECU was among them as before!

This is leading me to believe that there could be a deeper electrical issue. I'm going to try to test my module in a different car (might be tough) but was hoping to get some insight here before diving in. I had gotten to the shop late and we had no time to go further than this. The replacement module (that I'm not even sure I should have purchased now) is connected as we speak but seems to be doing nothing whatsoever.

NOTE: detailer did my exterior and went hard on my rims, SPECIFICALLY THE FRONT-RIGHT RIM. Granted, my issue seems like it isn't wheel sensor-related, but that is worth mentioning. I'll try to do some DMM tests this weekend on the connector at least. I have a bad feeling that the harness got fried.

QUICK FINAL NOTES:

-I drive a 2001 530i automatic
-From searching, I believe I have a Bosch 5.7 unit, part number ends in -001. The unit I got when I bought the car was already rebuilt by BBA as per the orange warranty sticker I see on it
-Since my problem's inception, the ASC and ABS lights have been ON all the time, no matter what, immediately upon starting the car
-Unplugged/reconnected battery - clock reset but nothing else (we know this, just saying)
-Clearing any codes using any scanner of any type, has never ever affected the ASC or ABS lights - see third point
-I have had no issues at ALL with brake-related dash lights
-My speedometer, odometer, trip meter, fuel consumption and cruise control all DO NOT work
-Gas gauge is not reliable, though it seems to find a happy place sometimes
-Gas consumption has increased (efficiency has decreased)
-Shifts are not as smooth and seamless as before, though not to the point of being at all "concerning"
-Tranny in sport mode is noticeably not as nice
-Since the wash, I've noticed my idle has become a bit odd - cold start it is slightly shaky (this was happening before but got a bit worse) and after slightly hard braking or constant braking in traffic the RPMs will dip right down to that one white line and vibrate a bit, then come back up to its expected spot.

THANK YOU FOR READING!

 

[edjack]

Sounds like you are the victim of a pressure wash. Good Luck.

Modern engines have many electrical connectors, and while they are well-sealed, most cannot stand up to a pressure wash.

 

[Hov5]

Sounds like you are the victim of a pressure wash. Good Luck.

Modern engines have many electrical connectors, and while they are well-sealed, most cannot stand up to a pressure wash.

I always do all the washing on my cars. One rim I used was the spare before so it was very, very bad, could not do it. Was in the same complex (seeing my mechanic) so I asked him to do the rims for me. Last second I asked for the engine too because it was pretty dirty (very clean rust-wise, just not cleaned for a long while). I should not have done that. I very deeply regret that now. Needless to say I've gone through the paces of being quite peaved about this

 

[djnvs]

Could have the same issue I had. When it would rain, or I'd have the car run through a car wash, my ABS/ASC lights would come on. Turned out to be my speed sensor for the back left wheel needed to be replaced. It was just really old and falling apart. Might want to check your wheel sensors just to be safe and eliminate them as the possible fault.

 

[GrannyApple]

Interdasting.

Since you said the connector had water I would check it and make sure theres no dried up soap or even any corrosion in there.

As for the engine diping on idle I would check for any air leaks and inspect the maf as well as the ICV.

Also could you post the codes up. That will help pinoint the roblem

 

[Hov5]

DJ - I was beginning to think that the rear 2 could be shot since speedo, odo, trip and cruise control all are not working.

I know its super rare for all 4 to go, but in aaaaall of these threads I didn't see one mention of water being a potential culprit - maybe that factor changes things (hopefully not)!

Also, if I can't get any communication from the ASC ECU, what else could it be? Is there a separate interfacing ECU or is it the ABS module itself that IS the ECU as well, and the harness simply gives it power and (is supposed to) allow communication as well? Seems like it must be either the module or the harness if not sensors.

I will test the connector using the wires-and-DMM method. I need a DMM though and it is Canada Day today so everything is closed - this will likely happen tomorrow.

Barracuz - kicking myself for not jotting them down yesterday. I have a small ODB II reader, I'll get what I can from it and post today.

I do have this one pic of one screen of the diagnostics program, giving ECU details. Top two lines seem potentially troublesome.

 

[rbail1]

pressure washed my engine bay a few months ago paying extra attention to the wheel wells (right front especially). After drying I started the car and the same thing with the abs light happened to me. I pulled the speed sensor from the socket because I was getting a speed sensor signal not plausible code. I sprayed out the connector on both sides with electrical connector cleaner and then let it dry. I also removed the speed sensor from the brake caliper and cleaned it out with brake cleaner and left them to dry out. After about an hour I buttoned it all up and took it for a drive. Within a block the light went out and has not returned. Start thoroughly cleaning all of the connectors and see what you get. Could be an exercise in futility or it could pay off. Either way you can rule that out and it's not an expensive place to start, just time consuming.

 

[bobdmac]

A code reader that can display live wheel speeds could help in ruling out the wheel speed sensors as the problem. Roll the car down the street and see if all four wheels read the same speed.

 

[Hov5]

I was considering getting INPA going shortly down the road if no other alternative seemed plausible. It would be handy to have set and available too.

As far as codes though, I'm getting the infamous one - P0500 - Vehicle speed sensor A. After clearing, engine light goes away but comes back soon after with the same code (20-30 km or so, maybe less).

I could not procure a multimeter today - I will borrow or buy one tomorrow and test the connector of the ABS module harness before going any further.

The big question is...if it is in fact a bad sensor (or more than one), would it cause the ASC ECU to be undetectable? Both of the modules I have right now are not even being detected by diagnostic tests (my indy mechanic has a big beefy ODB II reader that allows specific ASC/ABS communication but it says mine is not available, and I got the same result from the official BMW system his neighbour had hooked up). I'm wondering if this is just commonplace when there is an issue with that system somewhere, and once it's actually fixed and cleared the communication will come back along with the lights clearing from the dash (kind of like what happened for you rbail).

Mentioning rbail - a big fat thank you for that. It can't possibly hurt to do this so I'm going to give it a shot this weekend if I can find a place to get the car up and wheels off (might need to do it without though that is a PITA from what I've read).

In regards to what you cleaned - was it just the brake pad wear sensor and the wheel speed sensors? You mentioned connectors, I want to make sure I don't skip over anything simple while in the area. Thank you!

 

[Hov5]

The BMW system that is being used is BMW ICOM. I'm at the shop as we speak trying to get some diagnostics. I found a bent pin on the module - straightened and reconnected after blowing a lot of dust out of the connector. Will move onto cleaning wheel sensors after this if no progress is made.

 

[GrannyApple]

I was considering getting INPA going shortly down the road if no other alternative seemed plausible. It would be handy to have set and available too.

As far as codes though, I'm getting the infamous one - P0500 - Vehicle speed sensor A. After clearing, engine light goes away but comes back soon after with the same code (20-30 km or so, maybe less).

I could not procure a multimeter today - I will borrow or buy one tomorrow and test the connector of the ABS module harness before going any further.

The big question is...if it is in fact a bad sensor (or more than one), would it cause the ASC ECU to be undetectable? Both of the modules I have right now are not even being detected by diagnostic tests (my indy mechanic has a big beefy ODB II reader that allows specific ASC/ABS communication but it says mine is not available, and I got the same result from the official BMW system his neighbour had hooked up). I'm wondering if this is just commonplace when there is an issue with that system somewhere, and once it's actually fixed and cleared the communication will come back along with the lights clearing from the dash (kind of like what happened for you rbail).

Mentioning rbail - a big fat thank you for that. It can't possibly hurt to do this so I'm going to give it a shot this weekend if I can find a place to get the car up and wheels off (might need to do it without though that is a PITA from what I've read).

In regards to what you cleaned - was it just the brake pad wear sensor and the wheel speed sensors? You mentioned connectors, I want to make sure I don't skip over anything simple while in the area. Thank you!

To answer your question, as far as I'm aware no a bad sensor won't chase communication errors. I bet qsilver can answer that one. It will cause codes though.

Since the bay was pressure washed most likely water got into the unit and connector

 

[Hov5]

Sorry for being MIA on this - had some very busy times at work and it's my anniversary today too (she is still asleep!!)

Updates: was able to get some live readings while driving - all 4 sensors read 0 rpm (checked that the system works by confirming it is properly reading live data everywhere else such as tranny gear position and engine RPM).

I have not gotten around to removing, cleaning sensors and reattaching.

I took the used module I purchased back to the shop I got it from. He had no more so he sent it out to be rebuilt locally, should hopefully have it back by Monday.

Did some searching through he cables of the harness back about a foot and a half, saw no apparent breakage or damage. I hope I simply have 2 bum modules and this rebuild will fix it.

After that, onto recoding! But I I'll update here as I go to see what happens after a (hopefully) successful fix before recoding, difference in the car and lights before recoding, etc.

Thanks all!