Chrysler Repair: Fault code 43: 93 3.3L Coil Problem?, primary coils, driver circuits

Question

The check engine light has come on twice on my 1993 Voyager with 3.3L engine and DIS. I checked the fault codes by turning the ignition on and off and came up with code 43. My Chilton book says this is a coil primary circuit problem. I checked the coil primary and secondary resistances and they meet spec. What else could be wrong? Thanks, Jim


Answer
Hi Jim,
Other than the coil itself which you have verified,  the other possibilities are that 12V to drive the primary coils is not arriving on the dark green/orange wire from the ASD relay (but that would cause a total stall, or that the wiring from the pcm coil driver pins on one or more of the leads is intermittently open or shorted to ground if you don't sense a 'miss'. Those connections are pcm pin 17 dark blue/tan to dark blue/yellow at the coil pack, pin 18 dark blue/gray to red/yellow at the pack, and pin 19 black/gray to black/gray at the pack. If the wiring and the coil check out, then the only other explanation is the pcm is defective in one of its coil driver circuits. But I would not move on that until the engine began to noticeably miss.
Roland