Dealing with fault code 12 - distributor replacement?

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92_mr2
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Dealing with fault code 12 - distributor replacement?

Post by 92_mr2 »

Hi all, hope you can help!

Driving around the other day in my 92 NA import, CEL illuminated - no obvious change in performance (driving low speed around town anyway) - managed to get it home, stopped the engine and it will now not start. Managed to get it to idle for a short while but with more revs it struggled and eventually stalled. Sounds like it is almost catching but like it is not getting a consistent spark.

After bridging the diagnostic terminals I got code 12 (no signal to NE or G within 2 secs of cranking). BGB points to distributor circuit/starter or ECU. I don't have the best knowledge of the interior of the dizzy but think I read somewhere on here that 'NE' and 'G' are inside it, and that there's an internal oil seal that can go bad, with oil leaking into the dizzy and issues as a result - is it most likely a new distributor assembly needed? I've not yet had the chance to take anything off to inspect, but presumably this code could be caused by other faulty parts in the distributor circuit? (cap, rotor, HT leads, plugs etc). Before I start shopping for new bits/seeking professional help... is there anyone here with experience of this fault?

Thanks very much for looking


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Re: Dealing with fault code 12 - distributor replacement?

Post by jimi »

Presuming is as bad as assuming and you know what they say about assumptions !
The error does not relate to the plugs/leads/rotor or distributor cap. NE & G are both coils (think proximity switches) in the distributor that are triggered by the rotating cam inside the distributor, they send signals to the ECU plus a signal from the ignitor, the lack of any of these signals can cause error 12. When the BGB refers to the distributor circuit it's these LT circuits it's referring to not the HT circuit which isn't monitored by the ECU.
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92_mr2
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Re: Dealing with fault code 12 - distributor replacement?

Post by 92_mr2 »

Ah ha...this is all still a bit of a learning curve for me so thanks jimi that's really helpful - I guess that puts me in the market for a new distributor assembly/ignitor. Do you know if distributors are compatible between the 3SGE and GTE? And if so any difference between revisions/UK & import?

Thanks again

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92_mr2
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Re: Dealing with fault code 12 - distributor replacement?

Post by 92_mr2 »

Just adding to this for posterity/anyone having the same problem - turns out my ECU had failed. Repaired by the ECU Doctor, plugged in and it fired straight up first time, no CEL.

Looks like electronics of this age are starting to reach end of life so worth testing the unit if yours is behaving strangely!
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Re: Dealing with fault code 12 - distributor replacement?

Post by jimi »

Capacitor failure in MK2 ECU's is becoming increasingly common, certainly seems to be age related.
Funny enough enough similar failures in the MK1 ECU are pretty rare, can't recall hearing of any on the MK3, but it's relatively new in comparison with others.
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