still having problems with code 12 while running

[billygeg]

I am still getting this code 12 while the car is running. I tested everything. A is no shorted to B on the ALDL and, B is not grounded. There is a small section on the malfunction codes reference I printed out from gnttype.com that says...


Trouble Code 12 is a special case code that is not logged into the ECM's Non-Volatile Memory (NVM) when detected. When the ignition is "ON" and the ECM detects no ignition reference pulses coming from the ignition module, it illuminates the Service Engine Soon lamp.

What does this mean? Does it mean the ignition module could be bad?

Please help me out, Im going bald from pulling my hair out!

 

[Jerryl]

I am still getting this code 12 while the car is running. I tested everything. A is no shorted to B on the ALDL and, B is not grounded. There is a small section on the malfunction codes reference I printed out from gnttype.com that says...


Trouble Code 12 is a special case code that is not logged into the ECM's Non-Volatile Memory (NVM) when detected. When the ignition is "ON" and the ECM detects no ignition reference pulses coming from the ignition module, it illuminates the Service Engine Soon lamp.

What does this mean? Does it mean the ignition module could be bad?

Please help me out, Im going bald from pulling my hair out!

If the ignition module is bad or incorrectly wired, it would help explain the other ignition issues you are experiencing.

 

[billygeg]

If the ignition module is bad would the car still run though? This is driving me crazy! It runs but it runs very rough and stalls alot. The floor by the tailpipes is black from the carbon.

Thanks! Bill

 

[gsgns4me]

I am still getting this code 12 while the car is running. I tested everything. A is no shorted to B on the ALDL and, B is not grounded. There is a small section on the malfunction codes reference I printed out from gnttype.com that says...


Trouble Code 12 is a special case code that is not logged into the ECM's Non-Volatile Memory (NVM) when detected. When the ignition is "ON" and the ECM detects no ignition reference pulses coming from the ignition module, it illuminates the Service Engine Soon lamp.

What does this mean? Does it mean the ignition module could be bad?

Please help me out, Im going bald from pulling my hair out!

It means that when the ignition key is turned to "On" with the engine not running, the Check Engine Light will be illuminated (on steady). That's normal. Flashing or going out is not normal.

The engine is in running in base settings when Code 12 is flashing, ie: base timing, base fuel settings, open loop. It will not run properly when Code 12 is flashing no matter the reason (whether the ALDL is shorted with a pin or something else is causing it)

If the wires are not open, shorted, or grounded, then the ECM is probably faulty. If you follow the trouble trees in the service manuals to the letter with no shortcutting, it should give you the answer.

Disconnect the ECM connectors, turn the key on. Now what does the light do/don't do? Next step, leave the key on, with a test light connected to ground, probe circuit 419 (brown with a white tracer) on pin A5 of the smaller ECM connector (back probing is usually easier). What does the light do while probing? If it comes on, the ECM or connector is faulty. If it stays off, the problem is wiring related.

I don't believe any circuits in the ignition module are related to the CEL.

 

[billygeg]

I gotta give it another shot! I kind of hope its the ign mod or the ecm...If I have to trace wires! That will be alot of fun! NOT!

Thanks!

 

[gsgns4me]

What does the light do while probing?

Should have clarified, this is the CEL you are watching, not the test light.

 

[billygeg]

I just checked it with my son in the rain. He's pissed! Anyway, The light did not come on. Looking at the tree closer I noticed it says to check 451 or A9 for ground. I guess if its grounded in the field after the ECM I have a short somewhere. If its not, It must either be the computer or there is something triggering the computer to do this. Have to check tomorrow morning. There is no way in hell I'm going back out there again with my son. He's pissed already.

 

[Jerryl]

.......... Looking at the tree closer I noticed it says to check 451 or A9 for ground. I guess if its grounded in the field after the ECM I have a short somewhere. .........

The A9 wire goes to the ALDL.
When you put the car in diagnostic mode, you are in essence grounding that wire.

Can you disconnect/cut it at the ECM?
Maybe the easy way out, since you wil end up running powerlogger anyway. :wink:

 

[billygeg]

If I find out that its grounded in the field I can definitely cut it if thats not going to make a difference. I'm new so please explain to me what power logger is.
Thanks! I also noticed a funny looking plug under the ALDL. Is a small round plug attached to a white that runs under the console. My guess is it may be a factory thing for the guages but want to make sure. I dont have guages so its just hanging out there. Is it normal to be there or is this a rigged job?
Thanks!

 

[Jerryl]

If I find out that its grounded in the field I can definitely cut it if thats not going to make a difference. I'm new so please explain to me what power logger is.
Thanks! I also noticed a funny looking plug under the ALDL. Is a small round plug attached to a white that runs under the console. My guess is it may be a factory thing for the guages but want to make sure. I dont have guages so its just hanging out there. Is it normal to be there or is this a rigged job?
Thanks!

Sounds like a "rig job".
Don't cut the wire too close, if you are going to cut.
That way, it is easy to splice if you need to someday. :tongue:

Power logger is a laptop based scantool that has the ability to record and monitor everything the ECM is seeing at a 24 frame/second rate.
Whatever you choose for tuning aid/tool, you will need a scantool, period. :wink:

 

[billygeg]

I decided not to cut it for now. The B circuit is NOT shorted to ground and not shorted to A...I think its the ECM...Should I just get another ecm or try to replace the rom chip first?
Thanks!

 

[billygeg]

Hi
So in other words, You think it could be the ignition module thats causing it to code 12 while the car is on? I'm definitelty trying to get this right as not too go for a ECM and ingnition module.

Thanks!

 

[youngstr]

Sounds like your ECM could be stuck in diag mode, did you try unplugging the orange wire right near the battery? Its the ECM power line and when you unhook it the ECM should reset, if not then you might have a bad ECM, I don't know what else besides jumping the a & b terminals that would put it in diag mode. Try unhooking the ECM power, orange wire, 30 seconds then rehook.

 

[billygeg]

Yeah been there done that. I actually have the ecm sitting next to me now. Its watching me type...lol! I'm just afriad that it could possibly be the ignition module or the wires from it to the ecm. I know 12 is a normal code but why would they add that additional comment in the malfunction code decription abou code 12 if it meant nothing. I'd hate to buy the ecm and find out its the ign module or visa versa

 

[youngstr]

You could look at another way, If your ECM and Coil pack are both 84/85 stock then upgrading to the 87 ECM and Coil are already in your upgrade plans, in other words you would just be buying them later anyway....

If you have access to a junk yard that has late 80's cars in it, you can check the ECM list posted in this site and you can pull a good ecm and it won't cost you much, now the coil pack I would buy new, and that will cost you a bit, probably 150 ish

I see what you're saying about the that could could be the ECM saying it's not receiving the signal from the coil pack so it doesn't know if the pack if firing, so it goes into fail safe mode and uses the base tables for firing the plugs. That could also be a problem with the ig modual, or the wire that carries that signal from the ignition modual to the ECM. Did you test continuity on that wire back to the ecm?

 

[billygeg]

what is the benefit to the newer ignition? Is it that much better? If so, Why? What does it do that makes it so much better? I keep hearing about the upgrade and I'm thinking about it but not quite sure why...If I get a ignition module, coil pack, and ecm for a 86-87 Can I do the upgrade without changing the harness?

 

[youngstr]

yes, you can get a plug that plugs into the current wiring harness at the coil pack and connects to the 87 plug on the 87 ignition board, caspers electronics makes it, if you uses caspers part everything just plugs in, you still have to change the plate on the bottom of the 87 coil pack just like the upgrade coil link explains above.

There are several advantages to going to the 87 ECM and coil, you get to use the better chips from turbotweek, powerlogger, I think you can use the wideband chip from turbotweek too, if you plan on putting a wideband O2 in the car. Its your choice to do the upgrade, I was just saying that if you're gonna replace that stuff anyway, might as well do the upgrade and get the extra benefits over the 84/85 set up.

 

[billygeg]

I hear ya! I might just try it out...Costing much $$$ lol! just bought 2 front seats, 2 visors, seat belts, steering wheel, trunk lid, glove box, and 3 original decals all for $750 no bad huh? the money is starting to dwindle though! You mentioned a list of cars I can fine the ecm in at junk yards. Where is that list on this site? I might have to take a run and get one!

 

[billygeg]

I have a guy I may be able to get a 1987 ecm, ign module and coil pack from. My question is do I have to change the chip inside with mine or will it work just the way it is without swapping the chips out?
Thanks!

 

[youngstr]

I pulled this from the HOT AIR INFO STICKY, told ya theres a ton of info in those stickies, this is a list of all compatable ecm's for our cars.


ECM pn# 1227148 Here is a listing of all that use it:

1989 PONTIAC FIREBIRD TRANS AM V6 3.8L 231cid GAS FI T Engine VIN = 7
1989 PONTIAC FIREBIRD TRANS AM GTA SE V6 3.8L 231cid GAS FI T Engine VIN = 7
1987 BUICK REGAL GRAND NATIONAL V6 3.8L 231cid GAS FI T Engine VIN = 7
1987 BUICK REGAL LIMITED V6 3.8L 231cid GAS FI T Engine VIN = 7
1986 BUICK CENTURY CUSTOM V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 BUICK CENTURY ESTATE WAGON V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 BUICK CENTURY LIMITED V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 BUICK CENTURY T-TYPE V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 BUICK CENTURY V6 3.8L 231cid GAS FI N Engine VIN = B
1986 BUICK ELECTRA PARK AVENUE V6 3.8L 231cid GAS FI N Engine VIN = B
1986 BUICK ELECTRA T-TYPE V6 3.8L 231cid GAS FI N Engine VIN = B
1986 BUICK ELECTRA V6 3.8L 231cid GAS FI N Engine VIN = B
1986 BUICK LESABRE CUSTOM V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 BUICK LESABRE LIMITED V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 BUICK LESABRE V6 3.8L 231cid GAS FI N Engine VIN = B
1986 BUICK REGAL GRAND NATIONAL V6 3.8L 231cid GAS FI T Engine VIN = 7
1986 BUICK REGAL T-TYPE V6 3.8L 231cid GAS FI T Engine VIN = 7
1986 OLDSMOBILE 98 REGENCY V6 3.8L 231cid GAS FI N Engine VIN = B
1986 OLDSMOBILE 98 REGENCY BROUGHAM V6 3.8L 231cid GAS FI N Engine VIN = B
1986 OLDSMOBILE CUTLASS CIERA S V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 OLDSMOBILE CUTLASS CIERA V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 OLDSMOBILE DELTA 88 ROYALE V6 3.8L 231cid GAS FI N Engine VIN = 3
1986 OLDSMOBILE DELTA 88 ROYALE BROUGHAM V6 3.8L 231cid GAS FI N Engine VIN = 3