ECU: -118 and -122 Interchangeable?

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Keith
Posts: 68
Joined: Thu Feb 25, 2010 1:28 am
Location: SF Bay Area

ECU: -118 and -122 Interchangeable?

Post by Keith »

Greetings all,
Been out of touch here for a bit, and doing a search yielded few results. I just wanted to verify if anyone has used at later -122 ECU in exchange for a -188 in the 1979 cars? If so, have you had any problems?
Thanks.
-Keith
75 530i (5-speed)
93 M5 (4 liter stroker)
84 745i (5-speed)
T.Hanson
Posts: 1696
Joined: Wed Jul 26, 2006 7:39 am

Post by T.Hanson »

Expanding your question to any gurus):

'81 633 and 528, '79 528 all run fine. Each has an electronic control unit (ECU box) in the glove compartment, with the male pins and a big black female connecter, wire bundle going through the firewall.

I assume realoem will list part numbers of the ECUs. Numbers aside, are the ECUs from those years (79-81) the same ? Or do some of the little pins in one not do anything in the wrong, non-matching plug ?

I know the combo relay is the meeting place for the two separate wire harness bundles. I've been curious if the different aux air valves, sensors from year to year require that specific harness, that specific ECU, or if a smart electrical person could clip, snip adapt one set to another year's ends.
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