So Im driving down the road and my engine light comes on for the first time in forever. The car runs fine, but it's giving me a Code 12 when putting a paper clip in the terminal. A couple websites list this for a Code 12:

"This code will flash whenever the diagnostic terminal is grounded with the ignition in run, and the engine off. If this code appears while the engine is running, no reference pulses from the distributor are reaching the ECM. "

What does this mean or what needs fixed?

https://www.fiero.nl/cgi-bin/main.cgi?ECMCodes

Which I ask again, what does that mean?

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-Brady

Is it flashing 12 with the engine running? If not, The ECM is OK. If it is than you may have a broken wire from distributor or a bad distributor

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If you do the diagnostic test with the engine off, it is supposed to flash code 12. It does that to show you the ECM is working. It is NOT normal to see a code 12 if you do the diagnostic test with the engine running.

With the engine running and paperclip inserted the SES will flash each time for the O2 sensor crossover counts.

Code 12 means no EST pulses. EST pulses are the signals the distributor module sends to the ECM each time the pole pieces pass the stator in the distributor. If the engine isn't turning and the ECM and module have power then there won't be EST pulses. Since you can't check codes with the engine running you will, of course, always get a code 12 when pulling codes by grounding the ALDL terminal. If you were to cut the EST wire and start the engine it would not run because the EST pulses are what the ECM uses to time the injector firinggs.

JazzMan

Driving the car the past 2 days, the Check Engine light does still come on when the car reaches operating temperature. The car sill runs fine though, which makes we wonder if its an O2 sensor that has died. (I also find it odd that the light came on for the first time in almost 2 years the same day the mechanics had it)

When I use my paperclip to pull codes with the car *not* running, I get the Code 12. I find this odd because in the past, the car always remembered the codes, and I could check them with the car *not* running. But now there is nothing. So I dont know why I dont get any codes if the CE light has came on or why the car doesnt remember them. When I use the paperclip *with the car running*, the light just blinks steady. Ideas?

Bump for the weekend project :-)

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-Brady

The car has to be off to read the codes.... The codes are flashed three times.. The first is always 12... After you've seen code 12 flash 3 times, then the subsequent stored code(s) will flash... So if you have a code 13 set from an O2 sensor failure you would see:

12 12 12 -- 13 13 13 -- 12 12 12 -- 13 13 13 ......... This will continue as long as the ignition is on and the paper clip is inserted.

[This message has been edited by Poncho Jim (edited 09-21-2007).]

I unplugged the battery for a bit and checked the codes again. It's the dreaded Code 32. Yay for me! :-/

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-Brady