@djh3 Manual says the cps on it's own can be tested first either at the wiring for the sensor or pins 57 and 58. Spec of the sensor is listed at 280Ω. The second part is done at the pins so that's why they gave the option of starting there first.
A big "I think" because I'm only guessing. The voltage required to jump the gap in a spark plug is much higher than if you simply ground the electrode. The resultant voltage will be so low and fast that a digital meter may be too slow to even register it. The manual says any movement at all is good and I'm sure you'd get a better indication with a cheap meter with a needle. If that is the case then removing the plugs and grounding the electrode as they indicate will give a much easier path to ground and the digital meter would trigger on the current and you'd see the 2 - 5 volts listed.
Again, I'm guessing from what I'm reading.