Grrr. Its messing with me I think. Can anyone tell me if Im doing this the wrong way?

Engine light comes on after driving for a while.
Pull over, turn car off, insert diagnostics key into top row, far right holes, then turn ignition to on.

Code 12 every time.

Does anyone have an idea why it keeps throwing a clear code? Please help a n00b out.

 

If the malfunction doesn't last long enough it won't be put into permanent memory. Other then to keep driving it until the code is stored I don't know what else to tell you.

RBob.

 

Alright. I'll try and see what happens.

 

Just an FYI
code 12 isn't a code. All it means is there is no engine speed indication to the computer, probably because you did it with the car not running, it simply indicates that the computer diagnostic system is working correctly. Code 12 should be displayed three times, then and any other stored DTC codes will be displayed starting with the lowest number code, If code 12 is displayed another 3 times, the computer has not detected any other faults.

 

Have you tried running your car in the "Field Service Mode". Sometimes when the Engine Light comes on but there are NO codes, running in the "Field Service Mode" can revele small my-noot issues.

Invest $25 in a book by (Howell Engine Developments, INC.)

This book is all about Serviceing TPI's & LT-1"s.
It's well worth the money.

 

Diagnostic mode, A&B shorted, code 12 will flash three times, then any other trouble code will flash three times, then when all codes are done, it will end with code 12 flashing again to signify the end of codes. Basically if you see code 12 flash four times in a row, there are no codes.

 

Would a constant code 12 indicate anything wrong with the ECM itself? I am also getting code 12's which I've read is the handshake code as well as the no signal from distributor code (car off, ignition on) but my code 12's dosnt stop. It will continue to flash code 12 the entire time I have the paperclip inserted, even for 20 minutes straight. Anyone else ever seen this?

 

Its just running the diagnostic mode, mines does that also, that indicates the scm is not detecting any abnormalities, but i did get a 45 last friday.

 

Code 12 means the ECM did not detect any distributor reference pulses while in diagnostic mode. This is normal as the distributor is not spinning with the engine off. The lack of a code 12 could indicate an error in the diagnostic system. One possibility is that this actually is a problem with distributor reference pulses not getting back to the ECM. I've yet to come across this, and don't know if it even would be logged as an actual error as it will happen any time the key is on with the engine off, but IF it can be logged as a code, then you may have a problem in that system. This is the only "wierd" code and maybe it will take someone who's looked through the ECM code to comment whether it's possible.

 

if you weren't getting any pulses from the distributor, then the car wouldn't run. The ECM would never fore the injectors. You MIGHT have a spark if the Ignition Module did it as a backup source, but I don't think they do this on the FI models.