xmas drive woes.

[ExMX5owner]

My beloved z has been parked up for the wet season, Garaged of course. I thought I would take it for a xmas run. Darn, ASC switch dead and the orange light on. Other than that it drives well, Should I panic ?. or is there a remote possibility it will sort itself out, like most other thing do .... I did run the foxwell over it for good measure, NO faults. also tried to break traction, but the 2.0 cant do that anyway with the wheels that are on it, no matter how stupid I behave. The car itself has done 250k around about, no rust and pristine underside, well maintained, It just seems odd this should occur after a wet season stand up, being started every week or so, but not going anywhere, I,m hoping this has something to do with the voodoo that goes on in its brain.. Any guidance would be appreciated...

 

[NZ00Z3]

With the light on, there should be a code in the ASB module.

 

[ExMX5owner]

With the light on, there should be a code in the ASB module.

Nope, there is not, that is what has me confused, It would not be the first time Ive chased non existent faults with the car...She doesn't like not being driven, I'm almost certain... I ran the ..reader over it from the 20pin, and nothing, zero, zilch , zit, nada, diddly squat.... She behaves like a spoiled child that doesn't get any attention for months, And I just gave her an oil change because she wanted it after just over a year, and Ive only driven 950 ks. since her last one...I did forget to send her a xmas card though...I,m not sure where to look, or indeed if I have to... Right now I,m thinking, take it to a gravel carpark and go nuts, and observe results...

 

[Zephyr]

Hi mate.
No codes is a strange one.
charge the battery, because this is the easiest thing to do.
Pop out the fuse and check again. Maybe your scanner is not reading everything.
Then drive it for a while, most likely it will sort itself.
Check the brake light switch, sometimes it goes bad.
If nothing works, take it to a dealer to search for stored codes (shadow memory) and if nothing appears, start cleaning and checking wheel sensors, abs pump connections and pray.
sorry to hear that she is mad at you. But you should have known by now that if you do,not get intimate for a long time, thats what they do…

 

[ExMX5owner]

Hi mate.
No codes is a strange one.
charge the battery, because this is the easiest thing to do.
Pop out the fuse and check again. Maybe your scanner is not reading everything.
Then drive it for a while, most likely it will sort itself.
Check the brake light switch, sometimes it goes bad.
If nothing works, take it to a dealer to search for stored codes (shadow memory) and if nothing appears, start cleaning and checking wheel sensors, abs pump connections and pray.
sorry to hear that she is mad at you. But you should have known by now that if you do,not get intimate for a long time, thats what they do…

Update, Never got around to investigating the issue. But I took the old girl out for a good flogging this morning, the car that is...And the lights went out by themselves as you said, So me thinks I,m dealing with an intermittent gremlin... Cheers matey...

 

[Duncodin]

@Zephyr 's mention of the battery charge is interesting.

I regularly had that exact same problem after parking for a week which would sort itself out when the car was used. Car always started. I assumed it was just mucky sensors. Damp abs pump connector etc. So wasn't too bothered.

Unrelated - a while ago I had a flat battery problem. Put in a new battery thinking the battery was duff.

But now, thinking about it, i haven't had that ASC light on for quite sometime. So old battery was maybe a little low V and new battery fixed asc/abs issue too I'm thinking.

 

[Zephyr]

@Duncodin from what I was told, bmw has a very strange way to read electronic signals.
although the battery output is 12v the systems work with diodes that send 4.2 to 4.5v (for whatever reason) so when the battery is low on voltage the percentage of reduced power going to the sensors is less than 4.2 (dumb electrical cirquit reduces a static X amount of voltage it has in the input).
as a fellow software programmer you can understand that the case is P(output)=I(input)/X(constant percentage) while it should have beed P=I/x and the it should have an "if" and a "then" to adjust the percentage.
but that would require a constant control of the equation and with the ecu boards of the 90s (that thenZ3 carries) this would require a faster and more competent processor.
That is why Haldex and the rest after market ECUs were so expensive back in the day, because their processors could actually fly a plane (not that planes had any better ones but thats another story).
Today any arduino or rapsberry pi has eleven to twenty more times processing power than a 90s or 00s ECU and that is why people use them for tuning and replacement ecu's when they know a little pit of C, C++ or even Python.

 

[Zephyr]

Probably lots of misspelled words above, sorry, on a tiny mobile phone without readinf glasses.

 

[Duncodin]

Probably lots of misspelled words above, sorry, on a tiny mobile phone without readinf glasses.

Sounds like 'much cheapness' to me. The voltage regulators I used building industrial control systems as far back as1990 would reliably take any voltage between 8 and 20 and produce a reliable/smooth 5v output. That 5v would then be supplied to TTL level components. But, basically, it didn't matter what the actual supply was as long as it was 8v or more.

 

[Zephyr]

Sounds like 'much cheapness' to me. The voltage regulators I used building industrial control systems as far back as1990 would reliably take any voltage between 8 and 20 and produce a reliable/smooth 5v output. That 5v would then be supplied to TTL level components. But, basically, it didn't matter what the actual supply was as long as it was 8v or more.

Herr Hans Schnitzelhofen decided that for 2.600.000 vehicles he could save some 350.000 DM and get his bonus pills beer, so…

 

[Mike Fishwick]

Sounds like low battery voltage - I get this quite often if the car has been standing without being charged. The Slip control module isvery sensitive to supply voltage.
Give the car a short drive, then switch off and back on again - this always clears the problem.

 

[ExMX5owner]

Sounds like low battery voltage - I get this quite often if the car has been standing without being charged. The Slip control module isvery sensitive to supply voltage.
Give the car a short drive, then switch off and back on again - this always clears the problem.

It is entirely possible that this was its issue, I dont get to drive it much during the wet season. It still has half a tank of 91 in it that was put in by mistake months ago.