e36abs light

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dave525
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Post Mon Oct 29, 2012 10:03 am

hi,has anyone come across the abs/asc lights on and no communication with abs ecu on a 98 e36 328 cab? fuses seem ok. cheers
bss325i
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Post Mon Oct 29, 2012 10:40 am

Yes, dead ECU!

Check all power supplies and earths to ECU and if they are ok, get another ECU.

They are behind the glove box.
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dave525
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Post Mon Oct 29, 2012 12:30 pm

there seems to be lots of ecu,s behind the glovebox.Is there any way to identify which one the abs one is? cheers
bss325i
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Post Mon Oct 29, 2012 12:41 pm

Big metal one with ATE on it.
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stew72
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Post Mon Oct 29, 2012 12:46 pm

Before spending money on an ecu get hold of a wiring diagram and check that you're getting power where you should be and ensure all routes to earth are good. I recently had similar problems on a Renault scenic and 2 so called specialists blamed the ecu when it was simply a broken 5 amp feed for the ecu relay.
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Brianmoooore
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Post Mon Oct 29, 2012 1:39 pm

Not sure on the exact relevant build dates, or even if it ever applied to the E36, but some BMWs of around this age and slightly newer have what looks like an OBD2 socket in the cabin, but also have the old style round socket under the bonnet.
Not all diagnostics can be read from the socket in the cabin, however. Some need to be read from the old socket.
bss325i
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Post Mon Oct 29, 2012 3:51 pm

Brianmoooore wrote:Not sure on the exact relevant build dates, or even if it ever applied to the E36, but some BMWs of around this age and slightly newer have what looks like an OBD2 socket in the cabin, but also have the old style round socket under the bonnet.
Not all diagnostics can be read from the socket in the cabin, however. Some need to be read from the old socket.
No E36 had the twin diagnostic sockets.

E39's and E46's.
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bss325i
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Post Mon Oct 29, 2012 3:55 pm

stew72 wrote:Before spending money on an ecu get hold of a wiring diagram and check that you're getting power where you should be and ensure all routes to earth are good. I recently had similar problems on a Renault scenic and 2 so called specialists blamed the ecu when it was simply a broken 5 amp feed for the ecu relay.
bss325i wrote:Yes, dead ECU!

Check all power supplies and earths to ECU and if they are ok, get another ECU.
Obviously do some basic checks first but its not uncommon for an E36 ABS ecu to die, they are peanuts secondhand.

Also, make sure you get one from a car with the same transmission as yours as they are encoded for which transmission the car has and will put the traction control ASC light on if you have manual car and use one from an auto.
http://www.bmrperformance.co.uk

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Andyboy
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Post Mon Oct 29, 2012 4:02 pm

At least the sixes didn't have the E46 type ASC/ABS controller that the late 1.9 Compacts used - those go wrong fpr a pastime.

Regarding fuses, look at 46 (brake light switch and signal to ECU), 38 (ABS pump relay), 21 and 10 (ABS relay)
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Post Mon Oct 29, 2012 5:46 pm

Ive noticed some Z3's had the double sockets, late compacts are a coont, ive stripped the looms down on a few that have been destined for racing and they always play up :-x
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dave525
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Post Thu Nov 01, 2012 8:35 pm

Thanks to everyone for the help. Had the ecu tested and its dead. On with sourcing a replacement :)