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No power at A21/A22, No Spark

Posted: Sun Jan 04, 2026 9:34 pm
by Contella
Car went from running with occasional incidence where it felt like you turned off key for 1-2 seconds, to crank no start. Re-soldered a few pins on main relay that didn't look that bad, tried another relay, ( not really known good, from toolbox/junkyard, changed coil, ignitor.
Tested according to Helms and have power to all the other 'A's" and grounds on ecu pins/ plug.
Been using AI to probe around ecu traces and been getting some bs leads.
There's continuity to one leg of Q38 from A21and to one leg of a resistor right next to it, forget the number.
Anyone ever fixed this? Perplexity ai says run a jumper from A1 to A21 but I'd like to know which component will repair my ecu properly.
An ecu repair service with 100% feedback(?) on ebay has a customer who discussed sending his in with this issue (no power to ignitor)so I assume that was same issue and he repaired it?

I've been trying hard.
Sure would like to do it here if anyone knows.

Re: No power at A21/A22, No Spark

Posted: Sun Jan 04, 2026 9:35 pm
by Contella
Oh, and code 15 when it cranks....no jumper in harness..is it normal not to jump harness with s300? been a while since I installed it.

Re: No power at A21/A22, No Spark

Posted: Sun Jan 04, 2026 10:17 pm
by Contella
No more Perplexity, not for car info.

Led me on many fools errands.
New info says ecu is fine, bad ignitor. I tried a couple old ones I had, I can't believe they were all bad, we'll see.
Apparently the ignitor supplies the 10 volts not the ecu.