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I have a '94 sedan deville (4.9L) that has intermittent starting problems and when I go into the diagnostic mode all of the codes start with a "P" instead of an "E", of main interest is the code PO12. My Chiltons manual refers only to the "E" codes for my '94 caddy.

The main problem is the car won't start sometimes after its been run for awhile. Cap and rotor has been replaced. Has anyone had a problem like this and what about the codes and where would I go to get a full list of them?
 

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Id check the fuel filter...... A similar problem on my car, but not under my ownership.........
 

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P and E are the same. The're both referring to OBD1 Engine management computer. One stands for Powertrain, the other Engine.
 

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Well...sort of. The 1992 models used EOxx as the codes for 'engine.' In '93 and latter it changed to POxx for 'powertrain.'

So if a 1992 and 1993 car had the same code. It would be like this-

1992- EO36
1993- PO36

They are both the same code. Just a different prefix.

The latter OBDII codes are a completly different issue. Everyone uses the same codes and definitions. An example....OBDII code PO300 is the same thing on a Kia as it is on a Cadillac. PO300 is random engine misfire detected.

Logan
 

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Hi, I also have a '94 sedan deville (4.9L) and I am having the same problem as you are. I am having intermittent starting problems and P012 is also the code that is appearing in my OBD. I am very frustrated with the problem and it is currently in a automotive electrical shop. My car has been there 2 days now and they say everything is working fine, but I know better because I have had this problem for months and as soon as I think everythings OK I come out to leave and I'm stuck. The only thing that sometimes gets it to go is spraying some starter fluid under the air filter and sometimes that doesn't work. About six months ago I changed the dist cap and it was fine for a while, but then it went right back to the same thing. I was also told to change the pickup coil but I haven't tried it yet, have you changed yours? I have a book with the codes but you can also find them online under "Cadillac diag codes" or anything close to that. Please let me know if you have any luck with this problem. Or any other suggetsions that might be out there I'd appreciate them as well.




mattamatic said:
I have a '94 sedan deville (4.9L) that has intermittent starting problems and when I go into the diagnostic mode all of the codes start with a "P" instead of an "E", of main interest is the code PO12. My Chiltons manual refers only to the "E" codes for my '94 caddy.

The main problem is the car won't start sometimes after its been run for awhile. Cap and rotor has been replaced. Has anyone had a problem like this and what about the codes and where would I go to get a full list of them?
 

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Plugs and wires?? I bet this is the problem.....
 

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mattamatic said:
I have a '94 sedan deville (4.9L) that has intermittent starting problems and when I go into the diagnostic mode all of the codes start with a "P" instead of an "E", of main interest is the code PO12. My Chiltons manual refers only to the "E" codes for my '94 caddy.

The main problem is the car won't start sometimes after its been run for awhile. Cap and rotor has been replaced. Has anyone had a problem like this and what about the codes and where would I go to get a full list of them?
My service manual says that P012 means "no distributor reference signal". Here's a quote from the manual.

"The PCM checks for CAM HI pulses being received without REF HI (distributor) reference pulses. If the PCM senses no reference pulses, the engine will not start because the fuel delivery system is triggered by the reference pulses and Code P012 is set."

Follow that? I'm not sure I do. Here are the possible causes.

1. Open or shorts on CKT (circuit) 430 from ignition control module to PCM.
2. Ignition control module unable to process pickup coil signals to produce distributor reference pulses.
3. The grounding screw located on the metal tab that is attached to the plastic fitting on the five wire harness.

Is the p012 code current or history? If it's current, try wiggling CKT 430 (purple/white wire) and CKT 354 (red/black wire) at the distributor. An intermittant open will cause the engine to stumble. It that's not it, check the pickup coil leads.

There is a fault tree that on one of the pages to help narrow it down but I can't copy it. What it boils down to is checking for open or shorted connections in circuit 430 between the distributor and PCM. It could also be a failure of the PCM, ignition control module or pickup coil. Hope its not that.

If you cant find anything simple like a bad wire or connector, you may want to get it checked at a Caddy dealer. A good technician should be able to trouble shoot it. You don't want to diagnose by trial and error with the expensive parts like the PCM and ICM.

Good luck,
Perry
 

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Well I picked my car up from the automotive electrical repair shop after 3 days. They final got the car to act up but they couldn't figure out what was wrong, so I picked my car up brought it home and put it in the garage. Next, I pulled out my manual and decided to take some of the advice you guys gave me regarding the pickup coil. In the manual it gives a pretty easy way to test it without completely dissassembling your car. Basically you remove the dist cap and rotor cap then you get an ohm meter and test the leads. Mine tested fine so then I tested the ign coil and it tested fine, then I made sure that all of the leads were fastened tight. (Some of the leads can be pushed on and move out the other side, i.e instead of the male sliding in the female it pushes it back). Finally I made sure that the little piece that sits on the dist cap and sends spark to the rotor was on right.(It looked like mine was on backwards, part spring part metal) Once I put everything back together she started right up and started probably 30 times in the last week without any problems. Hopefully problem solved!!!!!!!:) Thanks for you input, maybe thats something for you to try Mattamatic.
 

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tdmellow said:
Well I picked my car up from the automotive electrical repair shop after 3 days. They final got the car to act up but they couldn't figure out what was wrong, so I picked my car up brought it home and put it in the garage. Next, I pulled out my manual and decided to take some of the advice you guys gave me regarding the pickup coil. In the manual it gives a pretty easy way to test it without completely dissassembling your car. Basically you remove the dist cap and rotor cap then you get an ohm meter and test the leads. Mine tested fine so then I tested the ign coil and it tested fine, then I made sure that all of the leads were fastened tight. (Some of the leads can be pushed on and move out the other side, i.e instead of the male sliding in the female it pushes it back). Finally I made sure that the little piece that sits on the dist cap and sends spark to the rotor was on right.(It looked like mine was on backwards, part spring part metal) Once I put everything back together she started right up and started probably 30 times in the last week without any problems. Hopefully problem solved!!!!!!!:) Thanks for you input, maybe thats something for you to try Mattamatic.
I'm glad you fixed it. It looks like it may have just been a bad connection.

I wonder what the repair shop was doing for those three days. You may not want to use them anymore.

Perry
 
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