SaabCentral Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter #1
I am posting this to hopefully help anyone who is getting codes P1312 or P1334. My car had P1312 recently and I found a good way to troubleshoot this problem. P1312 means that a misfire has been detected on cylinder 1 or 2. P1334 means that a misfire has been detected on cylinder 3 or 4. Cylinder 1 is the cylinder that is closest to the front of the engine where the pulleys and belts are located.

First, if you don’t have one, get a code reader that can tell you which cylinders are misfiring. Mine is an Ancel AD410. You can get one for $35 - $45. A Tech II also does this. On mine, you go into the OBDII, On-Board Monitoring section and you scroll down to “Misfire Cylinder 1”. Write down the numbers that you see there. (The first number is the number of previous misfires and the second number is the number of misfires on the current drive cycle.) Do the same for the other 3 cylinders. At this point, if your spark plugs are really old then you should replace them. If your spark plugs have been working fine and they’re not too old, move on to replacing the coil/coils that sit on top of the spark plug. Look at the list of misfires to see how many coils you need. Add one to that number so that you have an extra. When you get your new coil/coils, swap out the ones on the cylinders with the misfires with the new ones that you got. Drive the car around for a while and then check for misfires again using the code reader. No need to turn the car off. Just park it and plug in the code reader while it’s idling. This way you will get the number of misfires on the current drive cycle. Hopefully the misfire is gone.

I used the Professional Parts coils that are $43 on eEuroparts.com and haven’t had any problem at all with them. I know that people have written that you need to use the expensive OEM coils that have the raised SAAB logo on them or else you might get a cheap coil that is no better than the bad coil that you’re replacing. That may be true, but in my experience these coils have been great.

Something else that I wanted to mention is that in reading this forum I see where people have had code P1312 and they have tried to identify which coil is bad by swapping the ones in banks 1 and 2 over to banks 3 and 4. Then they can’t understand why there is still code P1312 instead of P1334. This could be because the code might not get set right away, even if there are misfires on the other cylinders, and the old code will still be there unless you have cleared it. That’s why I think that it’s better to troubleshoot the problem using a code reader where you can see which cylinders have misfires instead of moving coils around trying to figure out which one is bad.
 

·
Registered
Joined
·
38 Posts
Discussion Starter #2
Something else that I forgot to mention is that you can have misfires that don't cause the check engine light to come on, but you can tell that the car isn't running right. That's what happened to me a couple of years ago. It was starting to run badly due to misfires, but no trouble code. I replaced the spark plugs first. Didn't fix. Then I replaced all 4 coils. Fixed.
 

·
Super Moderator
Joined
·
9,061 Posts
P1312 is the t8 code for the ionization module falling 99.9999%,coil/s are going south(failing)..1312 doesn't related to any cylinders..
 

·
Registered
Joined
·
569 Posts
P1312 is the t8 code for the ionization module falling 99.9999%,coil/s are going south(failing)..1312 doesn't related to any cylinders..
Heh? Are you trying to say it is the ionization module or the coils?

I cured my p1312 code today by replacing coil pack no. 1 only. (Got lucky I guess - could have been no. 2 as well). Point being, nothing to do with the ionization module!
 

·
Registered
Joined
·
1,357 Posts
P1312 means "ionization signals implausible". <-- to the ECU.
There are a number of causes for this. Sooty plugs, bad coils, IDM, or ECU are just a few.
 

·
Registered
Joined
·
1,357 Posts
Makes sense, since a coil failure could make IDM signals that look like two cylinders firing at once, tripping the P1312.
 
1 - 7 of 7 Posts
Top