Join Date: Jun 2006
Location: Eastern ON Canada
Car: 07 OBW 2.5i D-4AT
Feedback Score: 5 reviews
On the MY2000+ (or roughly around then) there's no way to check the primary of the ignition coils in the coil pack.
The high voltage secondaries can be checked between the towers for cyl 1 and 2, and the towers for cyl, 3 and 4. As noted above, these should be in the 12 k Ohm range.
As shown in the attached diagram, the coil pack contains an integrated igniter circuit. The four connections at the electrical harness connector are 12V, ground, and two lines which carry trigger signals from the ECM. The 12 V and ground terminals can be measured (between them for a short), and between those two and the two trigger signal pins. All should have high resistance. (Some meters with a diode check range might show different resistances when the test probes are reversed.)
The earlier systems had a separate electronic igniter. With those, the high voltage secondaries, and the low voltage primaries (0.73 Ohms) of the coil could be checked at the terminals as shown above. With these, as subiesailor noted, the separate igniter has sometime been found to have failed.