1999-2009 [Subscribe to Daily Digest] |
2008 Saab 9-5 Sport
I had the notorious P1312 and P1334 appear a couple of months ago (had the codes pulled at AutoZone). The Zone gent said he had no idea what the codes meant. After researching these on the internet, I found the following detailed explanation of the codes:
P1312 - Combustion Detection cyl 1+2. Open Circuit / Short to B+
P1334 - Combustion Detection cyl 3+4. Open Circuit / Short to B+
So it sure seemed like a DIC starting to fail, although there were no starting or running issues. I decided to start at the plugs. I decided to put in a set of platinum plugs, because I know that these have an easier time firing a spark across a given gap. Sure enough some cheapo mechanic, or the prev. owner, had put $2.00 regular resistor plugs in there. So I replaced them with the platinums, and right away, I noticed a smoother running engine. As I said, it really didn’t have any running issues B4, but now it seemed “smoother”. And the CEL extinguished by itself within a couple of days. So maybe I got lucky, but I wanted to make a post here to thank this forum, and others, for guiding me through this CEL.
My rationale to the codes going away is this: The cheaper plugs make the DIC work harder to force the spark across the gap (newer platinum plugs conduct the spark better, because of the tiny center electrode). If the coils are working harder for this increased impedance, there’s a high probability that some of this high voltage can flash back or corona to the B+ (B+ is the 12V side of things). The new plat. plugs give the spark a more predictable path for the high voltage. Similar to the way a lightning rod works.
And I do carry a spare DIC in the trunk “just in case”.
posted by 199.46.198...
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