Where is the ABS ECU?

[andyborris]

I mean is it part of the ECU which controls the injection etc., or is it all in a separate box?

Because I've got 2 ECUs on my car, an original one above the glove box and a M50 one on the drivers side! I'm guessing the M50 one runs the engine, (cars got a M50 fitted).

But what effect will no longer being connected to the engine have on the original ECU?

Andy

[dazleeds]

above the glovebox fella

remove the black plastic cover and you cant miss it

[andyborris]

Thanks Daz,

Is it all in the one box, ABS, injection control and everything else?

Andy

[A1BMW325iSport]

drivers side - engine ecu, obc ecu

pass side - abs ecu, cruise control ecu

[andyborris]

Thanks, all clear now. The M50 ECU has simply replaced the M20 one and the ABS ECU is untouched.

Andy

[Brianmoooore]

Only connection between the two ECUs is that the M50 ECU controls its main DME relay, which switches a 12V+ on a red/yellow wire to the ABS ECU

[andyborris]

Pulling two threads together: This thread and this one http://www.e30zone.co.uk/modules.php?na ... ic&t=41862

ABS light on all the time in a M50 engined 325, relays checked by substitution with known good ones. No "3rd" relay on ABS ECU. Light goes out when 6 pin relay is pulled. I've checked the sensors (though I didn't expect that was the problem) and they're all good.

What is the C101? And is it fed from the DME relay via the red/yellow wire?

When you talk about the coil in the relay, do you mean the energising coil? And if I bypass this relay with a live feed, then the light should go out? And that means it's the ECU not switching the relay or live feed from the relay not "arriving"?

Sorry to be a pest and I'm not really bothered about having a working ABS, it's just become a bit of a challenge now !

Andy