HYDRAULIC UNIT SOLD
Zitat von sprucegoose
To recover my expenses on the ECU I am willing to sell the hydraulic unit to the first member of this forum willing to offer me at least £150 and who is prepared to collect it from me in person at the meet at CTL in Zeals on 11th November.
Sold, as agreed, to the first person who replied this morning.
SG
I've been a regular subscriber to the thread started by TallTony entitled "ASC + ABS Lights on, but now cured." My painful experiences have left me with a good hydraulic unit, albeit a used one which was replaced unnecessarily - I now wish to sell it to a good home.
If you are interested in BMW part no. 3 4.51-1 090 910, Bosch 0265 217 000, please go to that thread and check out my proposal.
SORRY, ITEM NOW SOLD
SG
Hydraulic Unit for sale!
The entire ABS/ASC circuitry has been checked OK, so the ECU has now been removed and sent for "remanufacturing" to BBA-Reman Ltd in Gillingham Kent. ( http://www.bba-reman.com ) . For £100 + £8.50 shipping + VAT = £127.49 they will return it to original specification - plus they provide a 2 year warranty. I'll be posting the outcome in due course and am really hopeful that this is the end of the road for my problem.
In the meantime, I've now obtained my original hydraulic unit back from the dealer as there is nothing known to be wrong with it, and in reality it was changed unnecessarily (see my posts above for a history of my experiences). To recover my expenses on the ECU I am willing to sell the hydraulic unit to the first member of this forum willing to offer me at least £150 and who is prepared to collect it from me in person at the meet at CTL in Zeals on 11th November. So, if you know for sure that you've got a "real" pump or valve problem, send me a private message with your offer. The BMW part no. is 3 4.51-1 090 910, the Bosch no. 0265 217 000. This is NOT an auction, just first come, first served. I'll reply personally to anyone who is interested and naturally, as soon as a deal is agreed, I'll edit this post to remove the item from sale. For the record, the car is a May 1997 build and had done 73,000 miles when it was removed - you should assume that the hydro-unit I am selling has been with the car from first registration in August 1997.
Looking forward to meeting up on the 11th.
Re: I don't believe it!!!
Zitat von sprucegoose..I am now going to do a thorough check of the wiring against section 3450.5b pages 3450.5-07 to 3450.5-12 to make sure that all wires are continuous and go where they should....SG
Sunday morning. I have performed a pin-by-pin continuity test and can confirm that these are the correct pages for a May 1997-build 840Ci Sport with M62-B44 motor. (BTW anyone who doesn't have the 1996 Electrical Troubleshooting Manual should let me know and I'll tell you where to find it) After testing all the wires (and I mean all, including such trivia as the incoming signal from the brake lights) I now agree with the garage that the only thing left which can be causing the fault is the ECU itself. The correct BMW part number for the ECU is 34 52 1 164 133 which has Bosch part number 0265 109 022. However, Bosch and their dealers cannot supply it directly as it is licensed for sale only through BMW, thereby doubling the price.
Good luck to everyone.
I don't believe it!!!
TT, save your prizes for a while. I went out in the car today and the problem has amazingly returned - with a vengeance. I am now going to do a thorough check of the wiring against section 3450.5b pages 3450.5-07 to 3450.5-12 to make sure that all wires are continuous and go where they should. I am really sorry guys, but all that theory just went right out of the window today. I will be working on it on and off this week and will post an update when I have something more concrete.
SG
A yes from the goose. Just need to get the day off, but should be do-able.
Sandwich
No chance its your relays???
SG
Time to leave well alone...?
Since fitting the new 25A BMW (pink) relays (BMW 8 365 326, Bosch 0 332 019 168) last week, there has been no further problems with the ABS/ASC lights. Although I have now obtained the higher spec Bosch 0 332 019 103s, I am reluctant to fit them yet, for fear of upsetting the applecart.
I do not believe now that the pump kicks in at ignition on - what I was hearing was the throttle control motor doing some kind of self test. I confirmed this by holding a finger on each relay as the ignition is turned on. There is no perceptible activity on K94 which remains in the OFF position, but K95 does two distinct clicks and then remains in the ON position if all is well. On occasions when there is lack of activity on K95, the system always goes to the failed condition if the lights have been momentarily on. I found that K94 can be removed after the system has settled down and this will not cause the lights to come on. So, I don't think this relay does much at all, until the slip control system is called upon to provide hydraulic pressure. So apparently one little pinky does all the hard work, and one little pinky does none! Mmm.
Kevin at Bosch told me that whenever a valve fault is signalled by the car, they always advise a supply and ground test to the connectors on the actual valve before changing anything. This is because any interruption or weakness of the power sources (all supplied through K95) can cause the ECU to flag a fault on the first valve on which it detects a low voltage. And that can be arbitrary, if the problem is nothing more than a weak relay. When I took the car in to have the hydro-unit replaced, the problem didn't go away, so the garage changed K94 and K95 round - but, and this is crucial, they didn't open the plastic casings to look at the contactors! After this action the lights were on pretty much all the time, a significant deterioration from the weeks before. With this final piece of evidence I now have the makings of a unified theory. Something like this....
K95 works very hard as it is permanently energised. After a finite period, the contacts erode and pit to some critical extent that lowers the voltage sufficiently for the ECU to see a fault on any one of the 10 valves in the hydraulic unit. You are now into the nightmare phase of an intermittent fault, which very slowly deteriorates until the lights might well stay on all the time. Along comes a smart owner who sees the two relays and decides to switch them over. In doing so, he puts a good relay (because its hardly ever been used) into K95 and with luck this will clear the fault for some further time. I think the reason my fault came on with a vengeance was because the garage did the switch a second time, replacing a cruddy relay at K95 with an even cruddier one.
So, what we may have here is nothing more than a part which wears out through normal use and needs replacing on a regular basis. Did I mention that later ECUs count the cycles and advise the technicians when to change the relays? So, maybe my idea of higher spec relays is pretty pointless, because even a higher current carrier will - eventually - succumb to pitting and metal transfer just the same. Maybe we just have to live with it.
One final puzzle for you. I've studied the wiring diagrams in section 3450.5 and believe that the correct schematic for a 1997 840Ci Sport with ASC/T is on page 3450.5.07, where the K94 and K95 relays are shown with a shunt resistor across pins 85 and 86. Yet the pink one's on my car don't have resistors whilst the higher spec ones identified by Bosch do have a resistor. Elsewhere, K94 and K95 are drawn without a resistor, e.g. 3450.5a. So is this just sloppy version control in the manual, or are different models fitted with different relays and, if so, why? Just a thought.....
Hope your problems go away.
SG
A note of caution...
TT and others, one thing just occurred to me. I need to check back with Kevin at Bosch to make sure that the standard ECU is up to providing the 160mA coil operating current. I shall do this before fitting the 0 332 019 103s. I'm 95% sure its OK but... better safe than sorry! Will let you know. BTW any of you ABS problem cases going to the proposed UK meet?
The pump?
NJ840, how did you conclude its the pump? Maybe you could say what you have done to arrive at this conclusion already. Bad news for you, but please share your experience.
SG
Upgrading K94
Firstly, I should point out that another day has passed, 2 short journeys have been made without further problems and my resolve is therefore strengthening that relay K94 is the guilty party in my ABS/ASC lights saga.
I contacted the technical support department at Bosch (UK) this morning and had an extremely fruitful 30 minute conversation with Kevin - this guy really knows about brake components! Convinced that the relay is under-spec'd I wanted to know if there is a bigger unit that would do the job and last a bit longer. Here's a precis of what I discovered:
Firstly, Bosch manufacture the entire shooting match including ECU, relays, sensors and pump unit. When a valve fault is diagnosed, he said it is still adviseable to conduct a wire-by-wire test on the supply and earth to the valve as false diagnoses are a distinct possibility. K95 is permanently energised whilst the ignition is on and provides the power supply to the valve array in the hydraulic unit (This is why its always quite warm to the touch). Recall that this relay is 25A and is protected by fuse F62, rated at 25A.
K94 provides the power to the hydraulic motor and, though also rated at 25A continuous, is protected by a special 50A fuse to cope with the additional inertial loads . On later BMWs and Mercs, the Bosch ECU has a counter which monitors the number of times the pump has been activated and advises "Change Pump Relay" automatically after a certain number of cycles. It might be 3 years, or 10, depending on the use of the vehicle, but the point is, someone has realised that this relay eventually wears out and has decided to incorporate its lifecycle into the on-board computer in newer cars. Interesting!
Anyway, I got the information I was seeking, in the form of a Bosch part number for a more robust relay. The standard 25A relay is BMW 8 365 326, which is Bosch 0 332 019 168. Tomorrow, I am picking up the replacement which is Bosch 0 332 019 103 and you can check the spec for yourself at http://www.chiefent.com/products/product_print.asp?id=10. As you'll see, this unit has a motor load of 40A (90A In-rush) and should be good for 150,000 cycles, having been tested from -40C to 100C, 95% humidity plus dust and salt spray testing. The price is under £4.00 so there'll be no tears if it doesn't work.
Let you all know what happens next.
Re: Pursuing the K94/K95 relays
OK, here we are a few days later, still there's been no problems with lights. I picked up new relays this morning (part no 8 365 326) and fitted them after confirming my understanding of the electric connections. When you stand on the left side of the car, relay K94 is nearest to you, K95 towards the centre of the car. The fuses F62 and F65 are also in this box. F62 is a standard 25A fuse, but F65 is peculiar. It is to be found underneath the adjacent plastic housing which can be removed easily with a small screwdriver and it looks like a computer chip. It is identified by its BMW part no. which is 8 365 901. Follow the high tension cable (red/brown) and you can see which pin of relay K94 is permanently hot.
I again removed the plastic locating plates, this time also the housing for the relay sockets and made a thorough job of cleaning and re-tightening each of the receptor contacts. After refitting everything, I tried numerous times to make the system fail but with no success. So far as I can tell therefore, for the time being at least, my previously "undetectable" problem seems to have gone away. I share this information so that, like arnie before me, at least one other owner might find that the root cause is nothing more than the relays and their connectors (I hope!).
With the new relays working satisfactorily, I then took the old ones apart to check the condition of the actual contacts. Nothing complicated about the relays, but one of them had a significant amount of pitting and metal transfer from one contact to the other. Was this enough to cause intermittent failure? More than likely. Anyway, I'm going to conduct a 2 week evaluation phase before deciding on a further course of action. The wiring diagram for the ECU pins, wheel sensors, hydro-unit, control valves and relays is available on the internet. To anyone with an alternative theory, questions or suggestions, please send me a private message.
ASC
The car was built in May 1997 and is an 840Ci Sport. Does that help?
Pursuing the K94/K95 relays
Having read NJ840, I decided to have an afternoon looking at things again. I found the K94/95 pump relays in their own plastic box just in front of the main fuse/relay box on the LHS. I shined up the gold-plated pins with a 1500 wet/dry paper, then removed the plastic locating plate to get at the sockets. Having cleaned them, I used a spectacle screwdriver on the contacts (just small enough) to obtain a tighter fit and put it all back together. I then did 10 small journeys, turning the engine off each time to release any residual hydraulic pressure in the accumulator. Result? No lights! I have ordered a pair of new relays (£7.80 inc VAT) as I am hoping that this is getting close to the heart of the problem. This morning was cold and foggy with a fine dew all over the car. Ignition on, 2 lights, 3 seconds later they both went out on schedule. Is it too early to get excited?
SG
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
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!
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
Seal included...
Richard
There is a new seal in the box with the glass.
Cheers
SG
Tony, the masking would be OK, but this would do nothing for the four inches of cold glass where the filaments have corroded. Re the Autoglass shop, its in Gatwick Road, Crawley, West Sussex phone 01293 613619. The chap who applied extra adhesive to seal out the moisture down the sides is called Ken. The BMW part (green glass with 3rd brakelight) is £440.08 including Vat and the BMW quote for the whole job was £950! By comparison, Autoglass was £581 all-in with a guarantee for as long as you own the car.
SG
My next job is to deal with the aircon fan which seems to have a shot bearing and which rattles when turning. Replacement is detailed in section 17-40/1 of the repair manual on Wuffer.Net.
An OEM replacement part is expensive, so I'm into either repair or second-hand replacement. Does anyone have a good one? Alternatively, is it possible to change the bearing? Any information would be gratefully received.
SG
