ASC + ABS Lights on

    Hi,


    A while ago I posted a thread about ASC + ABS lights being on at first intermitently and then more frequent and then permanently.


    After reading all the threads I could find on the issue both here and elsewhere, it appeared to be a faulty ABS Sensor, so I cleaned all these individualy by removing them from the wheel hubs (for those who do not know where they are; they sit just behind the brake discs, but you need to take the wheel off to get good access to them. Then a single allen key is needed to remove them, but if they are crusty, you'll need patience and controlled force to slide them out of their housing - plus a pack of Band-Aids/Plasters)


    All 4 of the sensors where covered in dirt, and had a lot of metal particles (like Iron Filings) attracted to the magnet that is the Tip of the ABS Sensor. Sprayed them with brake cleaner and scrubbed them with an old toothbrush and they came up like new. Refitted them all, fired up the engine, went for a short drive...... Lights still on. Damn.


    I had had a couple of diaognostic checks of the ECU done earlier and this threw up error codes of,


    1: ABS Return Pump Failure
    2: Wiring Fault (with a bunch of numbers I forget)


    apparently a faulty sensor throws this message up as it trips the ABS system out completely if one or more sensors is not functioning properly - but it provides a good excuse for the dealers to replace the whole pump unit at your expense - around £800 - £1000.


    A mechanic friend suggested disconnecting both batteries, drain the system of any charge by turing the key to position 2 and leaving it for 30 mins. Connect up the batteries and the stored ECU Error codes should be reset, as this does not happen even if the sensors are working properly.


    This did cure the problem. I have not had the lights on for a month now, so I have to assume that it was just dirty sensors.


    Just thought I'd pass my experience on to the board,


    Cheers


    Tony

    an update on the ABS ASC lights:


    They came on again recently, much to my annoyance. Decided to redo the original proceedure, wheel by wheel, and found yet more dirt attracted to the magnetic sensor tips - although nowhere near as much as the first time.


    Looking into the hole that they fit into I could see the disc the Sensors read, and this was still dirty, so I cleaned all the sensors up again and this time sprayed copious amounts of Brake Cleaner into the recepticle that the sensors fit in.


    After refitting I fired up the car and the lights went off and stayed off. No 'resetting' using the 'tip' I'd been given regarding the batteries.


    Now my guess is that I simply did not clean the sensors thouroughly enough the first time. :D


    Cheers


    Tony

    How are you getting on a month later


    TT
    I have this problem and its just as you describe, on for one journey, off for the next, on for a day, off for a week, back on again.....its definitely getting more frequent. So, how are yours at this time? I'm pretty confident the appearance of both ABS and ASC lights is due to the sensors as the repair manual states that the ASC utilises the ABS sensors - so there's the commonality. When cleaning them, did you notice any aspect of their appearance to suggest wear and tear taking place - i.e. is it worth looking at replacements instead?
    SG

    1997 E31 840Ci Sport
    2009 Mini Cooper
    2008 Toyota RAV-4 XT-R

    Do every act of your life as if it were your last.

    Hi SG,


    this thread you are looking at really only describes my incorrect fumblings around with my ASC ABS problem. The cause of my problems is featured in this thread here


    http://www.clube31.net/forum/v….php?t=3887&highlight=asc


    scroll down and look at the picture of the two ECUs, original/replacement :shock:


    My ASC ecu was completely shot-at, and since replacing I have had no problems whatsoever - in ASC department at least :lol:


    Hope it helps.

    TT
    So, do you think I should look at this connector first? Then, if that proves to be OK, should the next stage be the sensors? Thanks for your time.
    SG

    1997 E31 840Ci Sport
    2009 Mini Cooper
    2008 Toyota RAV-4 XT-R

    Do every act of your life as if it were your last.

    I guess it can't hurt to check, and is quicker, simpler and less painful on your knuckles than cleaning the ABS sensors (ask me how I know :D )


    The ASC ecu is located in the passenger doorsill. There are 3 boxes down there hidden away under the carpet. The one you want is closest to the engine bay. Simply unclip the connector and have a look at the pins. If they are corroded like mine was then that's your problem without doubt.


    Failing that then I'd look at the Sensors. These are a PITA to get out the first time, even though they are only held in place with 1 allen bolt. They are located behind the brake discs. I have removed and cleaned all 4 of them (twice) in my efforts to solve this 'lights on' issue. Mine were all crudded up with what looked like iron filings - they are magnetic - and a quick spray with brake cleaner, accompanied with an old (or enemy's) toothbrush cleaned them up. Also I sprayed copius amounts of cleaner into the aperture they fit into to try and dislodge as much of the dirt that accumulates in there.


    Disconnect the batteries for an hour, and then try again. If lights still come then at least you know it is not dirt causing the problem :?


    It may be one of the sensors is broken (for UK cars an OBD check is then required to ascertain which one) or worse, it could be the ABS pump (located under NS headlight unit). That's a pricey part from $tealers (£1300 + VAT), but you may find one from a breakers, or on ebay (.co.uk or .de).


    I hope you get it sorted mate - sadly it's an MOT fail with the ABS light on :cry:

    Not the ECU...


    Hi Tony
    Thanks a lot for the last information you posted. I found the ECU yesterday evening, just as you described. Everything down there was drizabone, the pins were all straight, and all in mint condition, looks as though its never been off.
    With the plug disconnected I turned on the ignition to see both lights illuminated. With the ignition still on I re-fitted the plug (quite a fiddle due to the angle....), and immediately both lights went out. From this test I have concluded that it has to be the sensors. Its just remotely possible that the plug has an intermittent bad contact, but I think that I shall now get the dealer to do the sensors as its still under warranty.
    Ironically, she's having a good spell at the moment and the lights are off!
    Thanks again.
    SG

    1997 E31 840Ci Sport
    2009 Mini Cooper
    2008 Toyota RAV-4 XT-R

    Do every act of your life as if it were your last.

    I have the same problem but about to be resolved. Just noticed a guy selling recon units on Ebay for £200.00 with 2 years warranty. Just need to check the BOSCH part number as he lists for the E39 but I understand they were the same unit..Also gives you £50.00 in p/ex for the old one...
    Is it true the dealers only give 6 months warranty on new ones?

    Diagnosis confirmed.....?


    After three months of ownership I still have the ABS/ACS lights problem, but at least I think I now know the answer. The supplying dealer had put it on his computer and it was diagnosed as an ASC valve fault. He's always agreed to fix the problem under warranty but wanted a second opinion before going ahead. The local BMW shop had it in last week and when they interrogated the car it was confirmed as the 'ASC Cross-over Valve' - whatever that is... Anyway, price of part circa £750 plus 3-4 hours labour, so this particular variant of the problem is not the one you want to have! Its being done early next week and on Saturday we're going to Scotland for a grand tour in our GT. For anyone still suffering this issue I'll post the results when I've got 1000 test miles on the clock.
    SG

    1997 E31 840Ci Sport
    2009 Mini Cooper
    2008 Toyota RAV-4 XT-R

    Do every act of your life as if it were your last.

    Zitat von sandwich

    I have the same problem but about to be resolved. Just noticed a guy selling recon units on Ebay for £200.00 with 2 years warranty. Just need to check the BOSCH part number as he lists for the E39 but I understand they were the same unit..Also gives you £50.00 in p/ex for the old one...
    Is it true the dealers only give 6 months warranty on new ones?


    They are not the same unit as the e39. These later ones (e38, e39) have the controller built in to the ABS value unit. the ones on the e31 have a separate controller in the passenger (UK, left) door sill.


    I have had the "ABS Return Pump Failure" error with accompanying ABS and ASC warning lights and have found this to occur on cold mornings, particularly when there is due. I disconnected and cleaned the connector to the ABS control unit and this fixed it for a while. Now it's back. Might be the connector on the actual ABS pump/valve block on the left side of the engine, in the left wing.

    Thanks Arnie. Dashboard now resembles the Blackpool Illuminations [Sorry Tony!] as theyve now been joined by the airbag light. Must got off my arse and sort it out...


    Looks like I'll be reading this thread for the next 5 hours

    Zitat von sandwich

    Thanks Arnie. Dashboard now resembles the Blackpool Illuminations [Sorry Tony!] as theyve now been joined by the airbag light. Must got off my arse and sort it out...


    Looks like I'll be reading this thread for the next 5 hours



    Check your batteries.
    If the voltage drops below about 8.5v during starting, it can cause many of these systems to show faults. I think the most common cause, however, seems to be the connectors. Disconnect the batteries, and check/clean all connectors with a contact-cleaner spray. The Carsoft 6.5 disgnostic kits (about Euro 90 on German ebay) are good for checking fault-codes and resetting lights.

    Doh! Still looking....


    We're still not there. The hydraulic unit has been serviced - fault still there. A replacement unit was fitted - fault still there. The garage is now working on the theory that one of the wires to the ECU has an intermittent discontinuity. Argonaut: if you also have fault code 34, hold on to your horses for a bit longer!

    1997 E31 840Ci Sport
    2009 Mini Cooper
    2008 Toyota RAV-4 XT-R

    Do every act of your life as if it were your last.

    Re: Doh! Still looking....


    Zitat von sprucegoose

    We're still not there. The hydraulic unit has been serviced - fault still there. A replacement unit was fitted - fault still there.



    Were the replacement test units new or used?



    I found recently, that when the ABS/ASC is behaving (no lights) that if you do some hard braking so that the ABS cuts in, then it can delay the re-occurance of the lights for many months, instead of the following day. It could be a problem with seizing components in the hydraulic unit.

    What to do next?


    Picked up the car yesterday and, as expected, the fault is still there. (And for the record its still intermittent). The garage have fitted a factory-recon hydraulic pump unit, so that can now be eliminated from the puzzle, along with all its valves to boot. Also, the ECU is (visibly at least) in A1 condition, as is the connector and wiring. Working on the assumption that the ECU is signalling fault No. 34 for some reason, they next tested the continuity of the wire to pin number 1 on the pump (green and white, I believe) and that showed a loss of 0.2 ohms between the pump unit and the ECU - i.e. negligible loss of current. So, guys, here's the 64K question: What does that leave? My guys now believe it must be in the ECU itself, unless anyone else can offer a different solution..... As I had a good result from BMW (UK) regarding the MID/OBC pixel problem (see my posts elsewhere) and given the amount of verbage on this forum regarding the ABS/ASC lights I am now going to send them another email to see if they acknowledge this problem too. Please submit anything that might help sort this out. If I get an answer from BMW, you'll be the first ones to know.
    Happy driving.
    SG

    1997 E31 840Ci Sport
    2009 Mini Cooper
    2008 Toyota RAV-4 XT-R

    Do every act of your life as if it were your last.

    Sorry to hear that the problem is not yet fixed.


    If the pump and hydraulic units have been replaced, and the wiring checked. that will just leave the ECU.


    It's possible that if the circuit concerned invloves analogue voltages, such as from a pressure sensor etc, that these circuits may have gone out calibration as components such as electrolytic capacitors have a finite life, and wear out after about 10 years or so. This could cause intermittent faults depending on temperature, use etc.


    Anyway, my car still shows intermittent ABS/ASC faults, although it did seem for a while that it had been cured after I cleaned the ECU connector.

    Mines going in next week to try and get to the root of the problem. I too have heard so many differing solutions so not sure which way to turn!
    I'll let you know if I find anything different.
    ABS and Airbag lights are still shining brightly!

    hi, I have the same issue.


    Hi everyone
    Just register here today.
    I have the same problem for a while already, I did tried replace the relay and cured for couple months, maybe you should give a shot before putting more money, K94 and K95 two pinkish abs reply in power box (mine are pink, 1994, 840), may involve different color with different year.
    hope will help
    Nick

Jetzt mitmachen!

Sie haben noch kein Benutzerkonto auf unserer Seite? Registrieren Sie sich kostenlos und nehmen Sie an unserer Community teil!

Benutzerkonto erstellen Anmelden