after installing the 550's, lex, fpr, fuel pump. I've got this misfiring sound. I checked the codes and it came up 12. I've checked all my CPS and coil pack wires and I can't find anything. could it be my starter? my starter either works or it doesn't, on a low battery it won't work at all but never slowly dies. any input?
code 12
- Thread starter madseacow
- Start date
I have a code 12 anomaly too. Three cps and a rewire, still intermittent 12. I think it's somewhere in the starter circuit, number three on the list of possibilities. I haven't been able to to a voltage drop test on the circuit yet.
One guy seems to have fixed his with a new ECU, number four on the list.
Take a look and see if any of that helps you:
http://www.supraforums.com/forum/showthread.php?t=410011
One guy seems to have fixed his with a new ECU, number four on the list.
Take a look and see if any of that helps you:
http://www.supraforums.com/forum/showthread.php?t=410011
I only glanced at that thread (SF is tough to swallow) but if the starter doesn't turn the engine as soon as you turn the key that problem needs to be addressed. The ECU wants to see NE just after it sees STA but it obviously won't if the engine doesn't actually crank. It's just a computer you know...not all that bright 
JJ - I was hoping you would catch wind of this thread or the one on SF.
Something you posted on mkiiitech, and I quoted on sf, lead me to concentrate on my starter circuit.
That and delayed starter operation, going through three cps, a rewire, new alternator, starter and battery pulled and tested good. I hear the starter relay but the starter doesn't turn over right away. This happens sporadically.
So I think I'm down to starter circuit or ecu.
madseacow - Sorry, I don't know what to think of the misfire and how it relates to the code 12, unless it is the CPS or the ECU. Though, I wouldn't jump to replacing the ECU. They have rarely been the problem. That's why their last on the list.
Guess I'm no help, except to say I'm in the same boat with an intermittent 12 with a delayed starter, sometimes.
Something you posted on mkiiitech, and I quoted on sf, lead me to concentrate on my starter circuit.
That and delayed starter operation, going through three cps, a rewire, new alternator, starter and battery pulled and tested good. I hear the starter relay but the starter doesn't turn over right away. This happens sporadically.
So I think I'm down to starter circuit or ecu.
madseacow - Sorry, I don't know what to think of the misfire and how it relates to the code 12, unless it is the CPS or the ECU. Though, I wouldn't jump to replacing the ECU. They have rarely been the problem. That's why their last on the list.
Guess I'm no help, except to say I'm in the same boat with an intermittent 12 with a delayed starter, sometimes.
Well, if the ECU sees STA (which is derived from the starter control signal) but the starter doesn't crank the engine the ECU isn't going to sample NE. That would lead to a code 12 the same as if the engine was cranked with a CPS problem. Sounds like you need a new starter or at least contacts. Might want to verify the code is being set only during starts. And yeah, voltage drop testing is an excellent method of finding minute resistance, especially on high current circuits. Works just as well with grounds too.