Obd1 CEL code 12 help (2 Viewers)

[Pz10420]

Well, kind of. Like I said my start battery is weak, but also my house(2nd) is getting old as well. I have found that if I completely isolate the 2nd battery from getting power while cranking the engine then I never have any weird noise or CEL. The start battery by itself cranks slowly but starts it everytime without any of the previous issues. I have not yet replaced either of the batteries yet, but I plan to soon.- So all that said I am not positive on the actual issue but I am leaning toward the dual battery set up having some kind of issue. Perhaps with the large solenoid pulling too many amps at the same time as the starter is cranking is just too much for 2 weak batteries. I plan to replace the start battery first and see what happens though.

 

[BakerFJ]

I've been experiencing code 12 as well, though I don't have a dual battery set up. All the distributor wiring to the ECM ohms out fine, I have also tested the distributor itself and swapped ECMs. This points me to the distributor being the problem child, however being that the distributor tests point to it being fine, I'd rather not spend the cheddar on a new dizzy unless I'm 100% sure that it's the issue.
I'll also note that on startup my battery voltage is within normal range.

Sometimes I can get it to start and run, and it'll idle just fine, sometimes even drive around. But it will eventually stall and won't start back up.
I don't have any weird sounds from my starter-- and both my battery and starter were replaced within this past year (general maintenance), I've also checked my fusible links as well.

Personally, I don't see how the starter signal circuit would affect the NE or G signal from the distributor to the ECM. If you look through the wiring schematics, their respective wiring really has nothing to do with one another.

I'm keen to figure out what exactly inside the distributor sends signal to the ECM. Of course my Land Cruiser is stranded at my parent's house about 45 minutes from my house.

I should also note that I do have a code for the ECT-- which would cause the engine to have a turn over but no-start issue. I'll be throwing one in next time I'm with the rig (full time college student for mechanical engineering). But would like to solve the Code 12 issue simultaneously, as I am not blessed with much free time during the semester.

 

[BakerFJ]

Unsure if you figured your issue out, but my code 12 ended up being an issue with the hall effect sensor internal to the distributor. There's no electrical test for this outlined in the FSM although if you're handy with signal reading I suppose you could. But it basically comes down to the air gap of the hall effect sensor or internal issues which can cause it to not send proper RPM signal to the ECU.
New distributor and I was on my way (as well as a battery because mine was kaput-- due to leaving the door open while fabricating custom mounting for Range Rover seats.... essentially drained the battery to nothing. Oops ).
Beyond that I also replaced my ECT and repaired the corrosion I found at the terminals to it which would have caused a fueling issue -- unrelated to code 12.

 

[LandLocked93]

Unsure if you figured your issue out, but my code 12 ended up being an issue with the hall effect sensor internal to the distributor. There's no electrical test for this outlined in the FSM although if you're handy with signal reading I suppose you could. But it basically comes down to the air gap of the hall effect sensor or internal issues which can cause it to not send proper RPM signal to the ECU.
New distributor and I was on my way (as well as a battery because mine was kaput-- due to leaving the door open while fabricating custom mounting for Range Rover seats.... essentially drained the battery to nothing. Oops ).
Beyond that I also replaced my ECT and repaired the corrosion I found at the terminals to it which would have caused a fueling issue -- unrelated to code 12.

Blyme! Range Rover strikes even on an LC.

 

[BakerFJ]

Blyme! Range Rover strikes even on an LC.

Captain's seats, heated, and all the adjustments including bolster! Not gonna hear me complaining

 

[LandLocked93]

Captain's seats, heated, and all the adjustments including bolster! Not gonna hear me complaining

View attachment 3593202

Ok lol best of two worlds.
Tokyo gets you there and back in the comfort of #10.
Classic.