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The first point to test is the capacitor itself. Enable precharge and measure of the change in voltage over the duration of the capacitor's charge. Note the time taken to fully charge the capacitors. It should follow the expected curve of voltage in an RC circuit. Now unpower the enable pin and measure the discharge. The times taken should be similar:
Precharge Precharge Discharge Discharge (Note: should be flipped as this is the charge graph)
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Repeat this test, except instead of checking the voltage on the capacitor, measure the test points COMP_OUT, AND_OUT, ISO_LATCH_OUT, LATCH_OUT, and ISO_2. The latter 4 should all be logic low to start and only send a 12V signal when the condition above is met. COMP_OUT will probably output a logic high when both pins are unpowered at the start. Note the times taken for each output to reach logic high. Also check the behaviour of LATCH_OUT to ensure it doesn't oscillate during the transition from logic high to logic low. Examples of transient tests can be seen in the related page posted above (recommended read for understanding of the board regardless). Example waveforms from MSXII testing:
As mentioned in Precharge Revisions, the comparator may output a logic high upon initial startup. As the capacitor starts charging, it'll output logic low until precharge is complete. The AND gate should only output logic high when the capacitor is finished precharging.
CAN tests:
Thermistor tests:
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