abs light

[bobafett]

Hi all, Jump started my car after leaving lights on over night and my abs light has come on. Car is 325 touring H plate 1991 help its for sale.....

[Templ8e30]

Iirc jump starting an ABS equipped E30 can fry the ABS relay.

Cheers,

Iain T

[Brianmoooore]

Iirc jump starting an ABS equipped E30 can fry the ABS relay.

Cheers,

Iain T

Only early ones though, I thought, with a seperate voltage protection relay mounted near the ABS ECU.

[Bigguns]

Iirc jump starting an ABS equipped E30 can fry the ABS relay.

Cheers,

Iain T

really? So how are you meant to charge your car battery?

[Brianmoooore]

Iirc jump starting an ABS equipped E30 can fry the ABS relay.

Cheers,

Iain T

really? So how are you meant to charge your car battery?

Disconnect one of its leads first.

[bobafett]

Iirc jump starting an ABS equipped E30 can fry the ABS relay.

Cheers,

Iain T

Only early ones though, I thought, with a seperate voltage protection relay mounted near the ABS ECU.

Cheers Brian, I know on the early ones there was a silver over voltage relay mounted above the glovebox catch area. On the later type is it the blue five pin relay mounted in the wiring breakout area behind the glovebox ? If so then is it just straight removal or does the memory have to be cleared after......

[Brianmoooore]

Blue relay at the back of the glovebox is the relay that allows the windows/roof to work with the doors open.
The silver voltage protection relay was simply deleted, presumably with the development of more robust electronics in the ABS ECU.
Three possibilities for you problem that I can think of:
1) Pure coincidence that an ABS fault has developed just as you jump started the car.
2) The ABS ECU has been swapped at some time for an early one that has succumbed to a voltage spike.
3) Later type ECU has been spiked anyway.
There's a diode in one of the relays on the ABS pump which I think can fail.

[bobafett]

Cheers Brian, will try relay one night this week...

[ShepsEvo3]

Right, I bought Bobafett's car, with the ABS and some other issues...

I have swopped the ABS ECU with a known good one and also the 2 relays ontop of the ABS Pump itself. The ABS light is still on. The ones off this car I have fitted to the donar and ABS light goes out as soon as engine is started, so obviously the ABS light is the cause of something else.

All the ABS sensors check out ok, even when rotating the wheel. Any help would be appreciated

Infact, the car does have some electrical issues if anyone is an auto-electrician and wouldn't meeting up to have a look/sort them? I am no electrician and don't really have time to mess with it to be honest!

[aus325]

Wish I could offer some help.. but I'm in exactly the same predicament.

I have also replaced both relays on the pump (brand new items), replaced the overvoltage relay above the glovebox (tested ok, but replaced with brand new item anyway), and a known good ABS ECU (tested in another car).

I have inspected as much of the wiring loom as possible, and have consequently just given up. Beyond fitting a new ABS pump,I'm out of ideas, and I know there are other zoner's who have faced this same problem.

One day the answer will come... I hope.

[seanboy]

Pull the ABS lamp out of the dash!

[ShepsEvo3]

Pull the ABS lamp out of the dash!

I think I should maybe wire it into the alternator circuit....otherwise, if an MOT guy does his test correctly, it would certainly fail if it didn't come on atall!

[ShepsEvo3]

Where is this over voltage relay? Any pics? Couldn't see anything else other than the ABS ECU above the glovebox, unless I am blind, mine doesnt have this??????

[gareth]

yours won't have it unless it's an early one.

i have a very similar problem. the pump, ecu and relays have been changed and all sensors are fine both static and when moving.

next call is a 'proper' bleeding session in the ABS pump.

my abs did work when i bought the car but had no bulb fitted... i guess an intermittent fault had been hidden in the past

[Brianmoooore]

I've got one like this as well, and one day, I WILL sort it - simply by swapping parts, if by no other way.
ECU and both relays have been checked by swapping them with parts in a good car, and swapping them back again, and found to be guiltless. Wheel sensors appear to be good, the light comes on before the car moves, and the rest of the ABS unit is just valves and a motor, so I can't see how it can possibly be a fault there.
That's everything eliminated, but the light still comes on.
Light appears to be fed from both a relay in the pump unit, and by the ABS. Possibly the first thing to do is seperate these wires and fit two warning lights.
Just a matter of finding the time!

[gareth]

hehe! you know how long i've been trying to find the time!!!!!

i suspect a lot of air in the pump could be the cause. i did boil the fluid big time when 'brake testing' a while ago and this seems to have provoked it...

[Brianmoooore]

i suspect a lot of air in the pump could be the cause. i did boil the fluid big time when 'brake testing' a while ago and this seems to have provoked it...

This could give a soft pedal, but there's no sensors anywhere to pick this up and turn the light on.

[gareth]

hehe! i'm getting deperate you see! there seemed to be some trapped air after the brake cooking proceedure and i never quite shifted it.

something andy pointed out to me is this:
http://www.e30zone.net/modules.php?name ... ic&t=71015
there is a chance that the abs packed up during the M30 swap. to be honest it was so long ago, i can't remember the chain of events that well! may be worth a look though. one thing, which one is the DMW relay?

[Brianmoooore]

DMW? DME relay is the main ECU relay. Usually the white one amongst the group of three (or group of two plus empty socket).

[Brianmoooore]

If you didn't wire pin 20 of the C101 on the engine loom side, then the ABS isn't getting any power, and I'm not surprised that the ABS light is on.

[gareth]

how's that for a typo!!!! i did mean the DME relay!!!
would that have been in the group that lived near the PAS reservoir? if so, i'll have to rummage under the drivers side of the dash as that's where they live now! the group is positioned differently on the M30 (E32) loom

i 'think' my ABS packed up before the M30 swap and only once the M30 was in did i find that there was no ABS bulb fitted. i'll have to compare the wiring diagrams and check through.

[Brianmoooore]

Check for 12 volts at pin 1 (red/yellow) of the ABS ECU with the ignition on.

[gareth]

will do! cheers brian!

[ShepsEvo3]

Now thats something I could check too! I have also checked all the fuses, but all are fine.

What is weird, unless I am being a little misled, apparently the ABS was fully working and functional before the battery went flat. Once "jump" started, the ABS light stayed on. What worries me is that the dash has been out at some stage and hasn't back in its correct position, the wipers work with the ignition off, none of the door light switches work, cigar lighter isn't working, rear electric window switches not working. I think the obc is retro fitted, and once i take the dash out to fit it back properly, I am expecting all sorts of nastyness behind there. Infact, I don;t even wanna think about it! lol

[gareth]

ok, i have no volts at pin 1 of the abs ecu (red/yel). i traced through to the C101 plug and the red/yellow wire has no breaks or anything odd up to that stage. on pin 20 on the engine loom, i have what looks to be either a brown/yellow or a blue/green wire... it started getting dark and raining a lot so i ran indoors before sussing which side of the '20' was pin 20!!!!

don't suppose you have any info on the C101 pinouts on a 1990 E30 325i manual touring and a 1988/9 E32 735i auto do you?

[Brianmoooore]

I've got the E30 C101 pinouts, but not the E32 ones, although they'll be largely the same.
Your ABS feed needs to come from the red/whites or red/blues on the main ECU relay.

[gareth]

...although they'll be largely the same.

annoyingly close but not close enough in this case!

i'll trace the wires though this weekend and see how i go.

i'll have to get some long multimeter leads as the relays are now above the pedals

[gareth]

you're right brian! (no suprise there!)
i've started another thread as i think a few other 335i's may be running about with no ABS for this reason and i've not seen it mentioned before. this is probably another one of the few basic mods needed to get the M30 wired in right but i've not seen it publicly mentioned before.
http://www.e30zone.net/modules.php?name ... 606#779606
let me know if you spot any errors? (i'm sure there will be some)

cheers again!